Our Values

Ethics: Our actions are founded on trust, honesty and integrity through open communications and adherence to the highest standards of personal, professional and business ethics.

Quality: Our commitment to quality drives us to make continuous improvements in our quest for excellence.

Diversity: We value diversity, as well as the dignity and worth of each employee, and believe that a diverse and inclusive workforce is critical to our continued success.

Value: We are committed to creating value for all stakeholders – employees, customers, investors and our communities – through the optimum development and utilization of our resources.

Service: We provide responsive, flexible service to customers and commit to preserving the environment, providing a safe work environment and improving the quality of life for employees where they live and work.

Our Vision

To be a pure-play general partner that creates exceptional value for all stakeholders through our ownership in ONEOK Partners by:

Our Mission

To create shareholder value by profitably providing reliable energy and energy-related services in a safe and environmentally responsible manner to our stakeholders through our ownership in ONEOK Partners.

April 5, 2016

Dear Shareholder:

You cordially are invited to attend the annual meeting of shareholders of ONEOK, Inc., which will be held at 9:00 a.m. Central Daylight Time on Wednesday, May 25, 2016, at ONEOK Plaza, 100 West Fifth Street, Tulsa, Oklahoma 74103.

The matters to be considered and voted on at the meeting are set forth in the attached notice of the annual meeting and are described in the attached proxy statement. A copy of our 2015 annual report to shareholders also is enclosed. A report on our 2015 performance will be presented at the meeting.

We look forward to greeting as many of our shareholders as possible at the annual meeting. We know, however, that most of our shareholders will be unable to attend. Therefore, proxies are being solicited so that each shareholder has an opportunity to vote by proxy. You can authorize a proxy over the Internet or by telephone. Instructions for using these convenient services are included in the proxy statement and on the proxy card. Of course, if you prefer, you may vote by mail by signing, dating and returning the enclosed proxy card in the enclosed postage-paid envelope.

If your shares are held by a broker, bank, trustee or other similar fiduciary, unless you provide your broker, bank, trustee or other similar fiduciary with voting instructions, your shares will not be voted in the election of directors or in certain other important proposals as described in the accompanying proxy statement. Consequently, please provide your voting instructions to your broker, bank, trustee or other similar fiduciary in a timely manner to ensure that your shares will be voted.

Regardless of the number of shares you own, your vote is important. I urge you to submit your proxy as soon as possible so that you can be sure your shares will be voted.

Thank you for your investment in ONEOK and your continued support.

Proxy Statement

This proxy statement describes important issues affecting our company and is furnished in connection with the solicitation of proxies by our Board of Directors for use at our 2016 annual meeting of shareholders to be held at the time and place set forth in the accompanying notice. The approximate date of the mailing of this proxy statement and accompanying proxy card is April 5, 2016.

Unless we otherwise indicate or unless the context indicates otherwise, all references in this proxy statement to “ONEOK”, “we,” “our,” “us,” the “company” or similar references mean ONEOK, Inc. and its predecessors and subsidiaries and references to “ONEOK Partners” or the “partnership” mean ONEOK Partners, L.P. and its subsidiaries.

The following questions and answers are provided for your convenience and briefly address some commonly asked questions about our 2016 annual meeting of shareholders. Please also consult the more detailed information contained elsewhere in this proxy statement and the documents referred to in this proxy statement.

Why did I receive these proxy materials?

We are providing these proxy materials in connection with the solicitation by the Board of Directors of ONEOK, Inc. of proxies to be voted at our 2016 annual meeting of shareholders and at any adjournment or postponement of the meeting. You are invited to attend our annual meeting of shareholders on May 25, 2016, at 9:00 a.m., Central Daylight Time. The meeting will be held at our company headquarters at ONEOK Plaza, 100 West Fifth Street, Tulsa, Oklahoma. For directions to the meeting, please visit our website at www.oneok.com.

Who is soliciting my proxy?

Our Board of Directors is sending you this proxy statement in connection with its solicitation of proxies for use at our 2016 annual meeting of shareholders. Certain of our directors, officers and employees also may solicit proxies on our behalf in person or by mail, telephone, fax or email.

Who may attend and vote at the annual meeting?

All shareholders who held shares of our common stock at the close of business on March 28, 2016, may attend and vote at the meeting. If your shares are held in the name of a broker, bank, trustee or other holder of record, often referred to as being held “in street name,” bring a copy of your brokerage account statement or a voting instruction card, which you may obtain from your broker, bank, trustee or other holder of record of your shares.

Please note: no cameras, recording equipment, electronic devices, large bags, briefcases or packages will be permitted in the meeting.

Will the annual meeting be webcast?

Our annual meeting also will be webcast on May 25, 2016. You are invited to visit www.oneok.com at 9:00 a.m., Central Daylight Time, on May 25, 2016, to access the webcast of the meeting.

Registration for the webcast is required. An archived copy of the webcast also will be available on our website for 30 days following the meeting.

How do I cast my vote?

If you were a shareholder of record at the close of business on the record date of March 28, 2016, you have the right to vote the shares you held of record that day in person at the meeting or you may appoint a proxy through the Internet, by telephone or by mail to vote your shares on your behalf. The Internet and telephone methods of voting generally are available 24 hours a day and will ensure that your proxy is confirmed and posted immediately. These methods of voting are also available to shareholders who hold their shares in our Direct Stock Purchase and Dividend Reinvestment Plan, our Employee Stock Purchase Plan, our 401(k) Plan and our Profit Sharing Plan.

You may revoke your proxy any time before the annual meeting by following the procedures outlined below under the caption “What can I do if I change my mind after I vote my shares?” Please help us save time and postage costs by appointing a proxy via the Internet or by telephone.

When you appoint a proxy via the Internet, by telephone or by mailing a signed proxy card, you are appointing John W. Gibson, Chairman of the Board, and Stephen W. Lake, Senior Vice President, General Counsel and Assistant Secretary, as your representatives at the annual meeting, and they will vote your shares as you have instructed them. If you appoint a proxy via the Internet, by telephone or by mailing a signed proxy card but do not provide voting instructions, your shares will be voted FOR the election of each proposed director nominee named in this proxy statement and FOR proposal numbers 2 and 3.

To appoint a proxy to vote your shares on your behalf, please select from the following options:

Voting Options

On a touch-tone telephone, call toll-free 1-866-883-3382, 24 hours a day, 7 days a week, until 11:59 p.m. (Central Daylight Time) on May 24, 2016.

What if my shares are held by my broker, bank, trustee or other similar fiduciary?

If your shares are held in a brokerage account or by a bank, trustee or other similar fiduciary, your shares are considered to be held “in street name.” If you held shares in street name as of the record date of March 28, 2016, this proxy statement and our 2015 annual report to shareholders should have been forwarded to you by your broker, bank, trustee or other similar fiduciary, together with a voting instruction card. You have the right to direct your broker, bank, trustee or other similar fiduciary how to vote your shares by using the voting instruction card or by following any instructions provided by your broker, bank, trustee or other similar fiduciary for voting via the Internet or telephone.

Under the rules of the NYSE, unless you provide your broker, bank, trustee or other similar fiduciary with your instructions on how to vote your shares, your broker, bank, trustee or other similar fiduciary will only be permitted to vote your shares on the ratification of the selection of our independent registered public accounting firm and will not be able to vote your shares on any of the other matters to be presented at the annual meeting. Consequently, unless you respond to their request for your voting instructions in a timely manner, your shares held by your broker, bank, trustee or other similar fiduciary will not be voted on any of these other matters (which is referred to as a “broker non-vote”).

Please provide your voting instructions to your broker, bank, trustee or other similar fiduciary so that your shares may be voted.

What can I do if I change my mind after I vote my shares?

If you were a shareholder of record at the close of business on the record date, you have the right to revoke your proxy at any time before it is voted at the meeting by:

If your shares are held in a brokerage account or by a bank or other similar fiduciary, you may revoke any voting instructions you

may have previously provided only in accordance with revocation instructions provided by the broker, bank, trustee or other similar fiduciary.

Is my vote confidential?

Proxy cards, ballots and voting tabulations that identify individual shareholders are mailed and returned directly to our stock transfer agent who is responsible for tabulating the vote in a manner that protects your voting privacy. It is our policy to protect the confidentiality of shareholder votes throughout the voting process. The vote of any shareholder will not be disclosed to our directors, officers or employees, except:

The vote tabulator and the inspector of election has been, and will remain, independent of us. This policy does not prohibit shareholders from disclosing the nature of their votes to our directors, officers or employees, or prevent us from voluntarily communicating with our shareholders, ascertaining which shareholders have voted or making efforts to encourage shareholders to vote.

Who will count the vote?

Representatives of our stock transfer agent, Wells Fargo Bank, N.A., will tabulate the votes and act as the inspector of the election.

How is common stock held in our 401(k) Plan and our Profit Sharing Plan voted?

If you hold shares of our common stock through our 401(k) Plan or our Profit Sharing Plan, in order for those shares to be voted as you wish, you must instruct the trustee of these plans, Fidelity Management Trust Company, how to vote those shares by providing your instructions via the Internet, by telephone or by mail in the manner outlined above. If you fail to provide your

instructions or if you return an instruction card with an unclear voting designation or with no voting designation at all, then the trustee will vote the shares in your account in proportion to the way the other participants in each respective plan vote their shares. These votes receive the same confidentiality as all other shares voted.

To allow sufficient time for voting by the trustee of our 401(k) Plan and our Profit Sharing Plan, your voting instructions must be received by May 22, 2016.

How will shares for which a proxy is appointed be voted on any other business conducted at the annual meeting that is not described in this proxy statement?

Although we do not know of any business to be considered at the 2016 annual meeting other than the proposals described in this proxy statement, if any other business is properly presented at the annual meeting, your proxy gives authority to John W. Gibson, Chairman of the Board, and Stephen W. Lake, our Senior Vice President, General Counsel and Assistant Secretary, to vote on these matters at their discretion.

What shares are included on the proxy card(s)?

The shares included on your proxy card(s) represent all of the shares that you owned of record as of the close of business on March 28, 2016, including those shares held in our Direct Stock Purchase and Dividend Reinvestment Plan and Employee Stock Purchase Plan, but excluding any shares held for your account by Fidelity Management Trust Company, as trustee for our 401(k) Plan and our Profit Sharing Plan. If you do not authorize a proxy via the Internet, by telephone or by mail, your shares, except for those shares held in our 401(k) Plan and our Profit Sharing Plan, will not be voted. Please refer to the discussion above for an explanation of the voting procedures for your shares held by our 401(k) Plan and our Profit Sharing Plan.

What does it mean if I receive more than one proxy card?

If your shares are registered differently and are in more than one account, you will receive more than one proxy card. Please sign and return all proxy cards, or appoint a proxy via the Internet or telephone, to ensure that all your shares are voted. We encourage you to have all accounts registered in the same name and address whenever possible.

Why did we receive just one copy of the proxy statement and annual report when we have more than one stock account in our household?

We have adopted a procedure approved by the Securities and Exchange Commission called “householding.” This procedure permits us to send a single copy of the proxy statement and annual report to a household if the shareholders provide written or implied consent. Shareholders continue to receive a separate proxy card for each stock account. We previously mailed a notice to eligible registered shareholders stating our intent to utilize this rule unless the shareholder provided an objection. If you are a registered shareholder and received only one copy of the proxy statement and annual report in your household, we will promptly deliver copies, to the extent you request them, for each member of your household who was a registered shareholder as of the record date. You may make this request by providing written instructions to Wells Fargo Shareowner Services, Attn: Householding/ONEOK, Inc., P.O. Box 64854, St. Paul, Minnesota 55164-0854. You also may contact Wells Fargo Shareowner Services in the same manner if you are currently receiving a single copy of the proxy statement and annual report in your household and desire to receive separate copies in the future for each member of your household who is a registered shareholder or if your household is currently receiving multiple copies of the proxy statement and annual report and you desire to receive a single copy in the future for your entire household. If you are not a registered shareholder and your shares are held by a broker, bank, trustee or other holder of record, you will need to contact that entity to revoke your election and receive multiple copies of these documents.

Is there a list of shareholders entitled to vote at the annual meeting?

The names of shareholders of record entitled to vote at the annual meeting will be available at the annual meeting and for 10 days prior to the meeting for any purpose relevant to the meeting between the hours of 9:00 a.m. and 4:30 p.m. CDT at our principal executive offices at 100 West Fifth Street, Tulsa, Oklahoma, and may be viewed by contacting our corporate secretary.

May I access the notice of annual meeting, proxy statement, 2015 annual report and accompanying documents on the Internet?

The notice of annual meeting, proxy statement, 2015 annual report and accompanying documents are currently available on our website at www.oneok.com. Additionally, in accordance with rules of the Securities and Exchange Commission, you may access this proxy statement, our 2015 annual report and any other proxy materials we use at okevote.oneok.com.

Instead of receiving future copies of our proxy and annual report materials by mail, shareholders may elect to receive an email that will provide electronic links to these proxy and annual report materials. Opting to receive your proxy materials online will save us the cost of producing and mailing documents to your home or business and also will give you an electronic link to the proxy voting site. You may log on to www.proxypush.com/oke and follow the prompts to enroll in the electronic proxy delivery service. If you hold your shares in a brokerage account, you also may have the opportunity to receive copies of these documents electronically. Please check the information provided in the proxy materials mailed to you by your broker, bank, trustee or other holder of record of your shares regarding the availability of this service.

What out-of-pocket costs will we incur in soliciting proxies?

Morrow & Co., LLC, 470 West Avenue, Stamford, Connecticut 06902, will assist us in the distribution of proxy materials and solicitation of votes for a fee of $11,000, plus out-of-pocket expenses. We also reimburse brokerage firms, banks and other custodians, nominees and fiduciaries for their reasonable expenses for forwarding proxy materials to our shareholders. We will pay all costs of soliciting proxies.

How can I find out the results of the voting at the annual meeting?

Preliminary voting results will be announced at the annual meeting. Voting results will be published in a Current Report on Form 8-K that we will file with the Securities and Exchange Commission within four business days after the annual meeting.

VOTING

Only shareholders of record at the close of business on March 28, 2016 are entitled to receive notice of and to vote at the annual meeting. As of that date, 210,097,064 shares of our common stock were outstanding. Each outstanding share entitles the holder to one vote on each matter submitted to a vote of shareholders at the meeting.

Shareholders of record may vote in person or by proxy at the annual meeting. All properly submitted proxies received prior to the commencement of voting at the annual meeting will be voted in accordance with the voting instructions contained on the proxy. Shares for which signed proxies are properly submitted without voting instructions will be voted:

(1) FOR the election of each of the 11 nominees for director named in this proxy statement to serve a one-year term;

(2) FOR the ratification of the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the year ending December 31, 2016; and

(3) FOR the advisory proposal to approve our executive compensation.

While we know of no other matters that are likely to be brought before the meeting, in the event any other business properly comes before the meeting, proxies will be voted in the discretion of the persons named in the proxy. The persons named as proxies were designated by our Board of Directors.

To vote shares held “in street name” through a broker, bank, trustee or other similar fiduciary, a shareholder must provide voting instructions to his or her broker, bank or other similar fiduciary. Brokerage firms, banks, trustees and other similar fiduciaries are required to request voting instructions for shares they hold on behalf of their customers and others. We encourage you to provide instructions to your brokerage firm, bank, trustee or other similar fiduciary on how to vote your shares. If your shares are held “in street name,” to be able to vote those shares in person at the annual meeting, you must obtain a proxy, executed in your favor, from the broker, bank or other similar fiduciary who held those shares as of the close of business on March 28, 2016.

The rules of the NYSE determine whether proposals presented at shareholder meetings are routine or non-routine. If a proposal is routine, a broker, bank, trustee or other similar fiduciary holding shares for an owner in street name may vote for the proposal without receiving voting instructions from the owner under certain circumstances. If a proposal is non-routine, the broker, bank, trustee or other similar fiduciary may vote on the proposal only if the owner has provided voting instructions. A “broker non-vote” occurs when the broker, bank, trustee or other similar fiduciary is unable to vote on a proposal because the proposal is non-routine and the owner does not provide any voting instructions. Under the rules of the NYSE, Proposals 1 and 3 are considered to be non-routine, and Proposal 2 is considered to be routine. Accordingly, if you do not provide voting instructions to your brokerage firm, bank, trustee or other similar fiduciary holding your shares, your brokerage firm, bank, trustee or other similar fiduciary will not be permitted under the rules of the NYSE to vote your shares on Proposals 1 and 3 and will only be permitted under the rules of the NYSE to vote your shares on Proposal 2 at its discretion.

Please provide your voting instructions to your broker, bank, trustee or other similar fiduciary so that your shares may be voted.

Representatives of our stock transfer agent, Wells Fargo Bank, N.A., will be responsible for tabulating and certifying the votes cast at the meeting.

QUORUM

The holders of a majority of the shares entitled to vote at the annual meeting, present in person or by proxy, constitute a quorum for the transaction of business at the annual meeting. In determining whether we have a quorum, we count abstentions and broker non-votes as present.

If a quorum is not present at the scheduled time of the meeting, the shareholders who are present in person or by proxy may adjourn the meeting until a quorum is present. If the time and place of the adjourned meeting are announced at the time the adjournment is taken, no other notice will be given. However, if the adjournment is for more than 30 days, or if a new record date is set for the adjourned meeting, a notice will be given to each shareholder entitled to receive notice of, and to vote at, the meeting.

MATTERS TO BE VOTED UPON

At the annual meeting, the following matters will be voted upon:

VOTES REQUIRED

Proposal 1 – Election of Directors.

Our By-laws provide for majority voting for directors in uncontested elections. We expect that the election of directors at our 2016 annual meeting will be uncontested. Under the majority voting standard, the election of directors is decided by the affirmative vote of a majority of the votes cast with respect to that nominee’s election by the shareholders present in person or by proxy at the meeting and entitled to vote for the election of directors. In other words, to be elected a nominee must receive a number of “for” votes that exceeds the number of “against” votes cast with respect to that director’s election. Abstentions and broker non-votes, if any, do not count as “for” or “against” votes cast with respect to the election of directors.

Our corporate governance guidelines require that if in an uncontested election a nominee for director does not receive the requisite majority vote, he or she must promptly, following certification of the shareholder vote, tender his or her resignation to our Board of Directors. The Board (excluding the director who tendered the resignation) will then evaluate the resignation in light of the best interests of our company and our shareholders in determining whether to accept or reject the resignation, or whether other action should be taken. In reaching its decision, the Board may consider any factors it deems relevant, including the director’s qualifications, the director’s past and expected future contributions to the company, the overall composition of the board and whether accepting the tendered resignation would cause the company to fail to comply with any applicable rule or regulation (including NYSE listing requirements and the federal securities laws). The Board will

act on the tendered resignation and publicly disclose its decision and rationale within 90 days following certification of the shareholder vote.

Proposal 2 – Ratification of Selection of PricewaterhouseCoopers LLP as our Independent Registered Public Accounting Firm for the Year Ending December 31, 2016.

Proposal 3 – Advisory Vote on Executive Compensation.

In accordance with our By-laws, approval of each of Proposals 2 and 3 requires the affirmative vote of a majority of the voting power of the shareholders present in person or by proxy and entitled to vote on each proposal at the meeting. Abstentions will have the same effect as votes against Proposals 2 and 3 and broker non-votes do not count as entitled to vote for purposes of determining the outcome of the vote on Proposal 3.

REVOKING A PROXY

Any shareholder may revoke his or her proxy at any time before it is voted at the meeting by (1) notifying our corporate secretary in writing (the mailing address of our corporate secretary is 100 West Fifth Street, Tulsa, Oklahoma 74103), (2) authorizing a later proxy via the Internet or by telephone, (3) returning a later dated proxy card, or (4) voting at the meeting in person. A shareholder’s presence without voting at the annual meeting will not automatically revoke a previously delivered proxy and any revocation during the meeting will not affect votes previously taken.

If your shares are held in a brokerage account or by a bank, trustee or other similar fiduciary, you may revoke any voting instructions you may have previously provided in accordance with the revocation instructions provided by the broker, bank, trustee or other similar fiduciary.

PROXY SOLICITATION

Solicitation of proxies will be primarily by mail and telephone. We have engaged Morrow & Co., LLC, 470 West Avenue, Stamford, Connecticut 06902, to solicit proxies for a fee of $11,000, plus out-of-pocket expenses. In addition, certain of our officers, directors and employees may solicit proxies on our behalf in person or by mail, telephone, fax or email, for which such persons will receive no additional compensation. We will pay all costs of soliciting proxies. We will also reimburse brokerage firms, banks and other custodians, nominees and fiduciaries for their reasonable expenses for forwarding proxy materials to our shareholders.

Our Board of Directors and management are committed to maintaining strong corporate governance practices that allocate rights and responsibilities among our Board, management and our shareholders in a manner that benefits the long-term interest of our shareholders. Our corporate governance practices are designed not just to satisfy regulatory and stock exchange requirements, but also to provide for effective oversight and management of our company.

Our Corporate Governance Committee engages in a regular process of reviewing our corporate governance practices, including comparing our practices with those recommended by various corporate governance authorities, the expectations of our shareholders and the practices of other leading public companies. Our Corporate Governance Committee also reviews regularly our corporate governance practices in light of proposed and adopted laws and regulations, including the rules of the Securities and Exchange Commission and the rules and listing standards of the NYSE.

CORPORATE GOVERNANCE GUIDELINES

Our Board of Directors has adopted corporate governance guidelines that address key areas of our corporate governance, including: the Board’s mission and responsibilities; Board membership and leadership; the structure and function of the Board’s committees; meetings of the Board and its committees, including attendance requirements and executive sessions; Board compensation; Board and officer share ownership requirements; succession planning; evaluation of the performance of our Board; and Board access to management and independent advisors. Our Board periodically reviews our corporate governance guidelines and may revise the guidelines from time to time as conditions warrant. The full text of our corporate governance guidelines is published on and may be printed from our website at www.oneok.com and is also available from our corporate secretary upon request.

CODE OF BUSINESS CONDUCT AND ETHICS

Our Board of Directors has adopted a code of business conduct and ethics that applies to our directors, officers (including our principal executive and financial officers, principal accounting officer, controllers and other persons performing similar functions) and all other employees. We require all directors, officers and

employees to adhere to our code of business conduct and ethics in addressing the legal and ethical issues encountered in conducting their work for our company. Our code of business conduct and ethics requires that our directors, officers and employees avoid conflicts of interest, comply with all applicable laws and other legal requirements, conduct business in an honest and ethical manner and otherwise act with integrity and in our company’s best interest. All directors, officers and employees are required to report any conduct that they believe to be an actual or apparent violation of our code of business conduct and ethics.

The full text of our code of business conduct and ethics is published on and may be printed from our website at www.oneok.com and is also available from our corporate secretary upon request. We intend to disclose on our website any future amendments to, or waivers from, our code of business conduct and ethics, as required by the rules of the Securities and Exchange Commission and the NYSE.

DIRECTOR INDEPENDENCE

Our corporate governance guidelines provide that a majority of our Board of Directors will be “independent” under the applicable independence requirements of the NYSE. These guidelines and the rules of the NYSE provide that, in qualifying a director as “independent,” the Board must make an affirmative determination that the director has no material relationship with our company, either directly or as a partner, shareholder or officer of an organization that has a relationship with our company. In making this determination with respect to each director serving on the Executive Compensation Committee, under the rules of the NYSE, the Board is required to consider all factors specifically relevant to determining whether the director has a relationship to our company which is material to that director’s ability to be independent from management in connection with the duties of a member of that committee.

Our Board of Directors has also adopted director independence guidelines that specify the types of relationships the Board has determined to be categorically immaterial. Directors who meet these standards are considered to be “independent.” The full text of our director independence guidelines is published on and may be printed from our website at www.oneok.com and is also available from our corporate secretary upon request.

Our Board of Directors has determined affirmatively that members James C. Day (who will retire from our board immediately prior to our annual meeting of shareholders on May 25, 2016), Brian L. Derksen, Julie H. Edwards, Randall J. Larson, Steven J. Malcolm, Kevin S. McCarthy, Jim W. Mogg, Pattye L. Moore, Gary D. Parker and Eduardo A. Rodriguez have no material relationship with our company, and each qualifies as “independent” under our corporate governance guidelines, our director independence guidelines and the rules of the NYSE. Accordingly, 10 out of our current 12 directors qualify as independent.

BOARD LEADERSHIP STRUCTURE

During 2015, our Board was led by John W. Gibson, who is our non-executive Chairman of the Board, in consultation and coordination with Jim W. Mogg, who is our lead independent director and the Chairman of the Corporate Governance Committee. In addition, our Audit Committee and Executive Compensation Committee are each led by a chair and vice chair, each of whom is an independent director.

Our corporate governance guidelines provide that our Board of Directors retains the right to exercise its discretion in combining or separating the offices of the Chairman of the Board and Chief Executive Officer. Our Board reviews the issue as a part of its succession planning process. The Board believes that it is advantageous for the Board to maintain flexibility to determine on a case-by-case basis and, if necessary, change the Board leadership structure in order to meet our needs at any time, based on the individuals then available and the circumstances then presented.

The Board believes that maintaining Mr. Gibson’s continuing service as non-executive Chairman of the Board provides the most effective leadership model for our Board and our company. In making this determination, the Board considered the advantages to our company of maintaining the continuity of

Mr. Gibson’s effective leadership as Chairman of the Board based on, among other factors, his lengthy service as an executive officer of our company, including as chief executive officer from 2007 until his retirement on January 31, 2014, his strong leadership skills, his extensive knowledge and experience regarding our operations and the industries and markets in which we compete, as well as his ability to promote communication and to synchronize strategic objectives and activities between our Board and our senior management. The Board also believes this leadership structure continues to ensure significant independent oversight of management, as Mr. Spencer is the only member of the Board who is also an employee of our company, and Messrs. Gibson and Spencer are the only members of the Board who do not meet the independence criteria set forth in our corporate governance guidelines, our director independence guidelines and the independence criteria established by the NYSE. In addition, our Board has an ongoing practice of holding executive sessions, without management present, and executive sessions of the independent members of the board as part of each regularly scheduled in-person Board meeting.

In accordance with our corporate governance guidelines, the Board continues to retain the authority to combine the positions of Chairman and Chief Executive Officer in the future if it determines that doing so is in the best interests of our company and our shareholders.

LEAD INDEPENDENT DIRECTOR

Our corporate governance guidelines vest the lead independent director who, under these guidelines, is also chair of our Corporate Governance Committee, with various key responsibilities, including leading the Board’s process for selecting both the Chairman of the Board and the Chief Executive Officer. The guidelines provide that the lead independent director shall have served as a director for a minimum of three years, shall serve for a term of three to five years as determined by the Board of Directors, and that the duties of the lead independent director include but are not limited to:

In addition, the lead independent director has the authority to call meetings of the independent directors and, if requested by major shareholders, will ensure that he or she is available for consultation and direct communication.

SUCCESSION PLANNING

A key responsibility of the Chief Executive Officer and the Board is ensuring that an effective process is in place to provide continuity of leadership over the long term at all levels in our company. Each year, succession-planning reviews are held at every significant organizational level of the company, culminating in a full review of senior leadership talent by our independent directors. During this review, the Chief Executive Officer, the Chairman of the Board and the independent directors discuss future candidates for senior leadership positions, succession timing for those positions and development plans for the highest-potential candidates. This process ensures continuity of leadership over the long term, and it forms the basis on which our company makes ongoing leadership assignments.

OUR BOARD AND CORPORATE STRATEGY

Our Board of Directors is actively involved in overseeing, reviewing and guiding our corporate strategy. Our Board formally reviews our company’s business strategy, including the risks and opportunities facing our company and its businesses, at an annual strategic planning session. In addition, long-range strategic issues, including the performance and strategic fit of our businesses, are discussed as a matter of course at regular board meetings. Our Board regularly discusses corporate strategy throughout the year with management formally as well as informally and during executive sessions of the Board as appropriate. As discussed in “Risk Oversight” below, our Board views risk management and oversight as an integral part of our strategic planning process, including mapping key risks to our

corporate strategy and seeking to manage and mitigate risk. Our Board also views its own composition as a critical component to effective strategic oversight. Accordingly, our Board and relevant Board committees consider our business strategy and the company’s regulatory, geographic and market environments when assessing board composition, director succession, executive compensation and other matters of importance.

RISK OVERSIGHT

We engage in an annual comprehensive enterprise risk-management (“ERM”) process to identify and manage risk. Our annual ERM assessment is designed to enable our Board of Directors to establish a mutual understanding with management of the effectiveness of our risk-management practices and capabilities, to review our risk exposure and to elevate certain key risks for discussion at the Board level. Risk management is an integral part of our annual strategic planning process, which addresses, among other things, the risks and opportunities facing our company.

Our ERM program is overseen by our Chief Financial Officer. The program is a companywide process designed to identify, assess, monitor and manage risks that could affect our ability to fulfill our business objectives or execute our corporate strategy. Our ERM process involves the identification and assessment of a broad range of risks and the development of plans to mitigate these risks. These risks generally relate to the strategic, operational, financial, regulatory compliance and human resources aspects of our business.

Not all risks can be dealt with in the same way. Some risks may be easily perceived and controllable. Other risks are unknown. Some risks can be avoided or mitigated by particular behavior, and some risks are unavoidable as a practical matter. For some risks, the potential adverse impact would be minor and, as a matter of business judgment, it may not be appropriate to allocate significant resources to avoid the adverse impact. In other cases, the adverse impact could be significant, and it is prudent to expend resources to seek to avoid or mitigate the potential adverse impact. Management is responsible for identifying risk and risk controls related to our significant business activities;

mapping the risks to our corporate strategy; and developing programs and recommendations to determine the sufficiency of risk identification, the balance of potential risk to potential reward and the appropriate manner in which to control and mitigate risk.

The Board implements its risk oversight responsibilities by having management provide periodic briefing and informational sessions on the significant voluntary and involuntary risks that our company faces and how our company is seeking to control and mitigate those risks. In some cases, as with risks relating to significant acquisitions, risk oversight is addressed as part of the full Board’s ongoing engagement with the Chief Executive Officer and management.

The Board annually reviews a management assessment of the various operational and regulatory risks facing our company, their relative magnitude and management’s plan for mitigating these risks. This review is conducted in conjunction with the Board’s review of our company’s business strategy at its annual strategic planning meeting and at other meetings as appropriate.

We also maintain a Risk Oversight and Strategy Committee, which consists of our senior management. This committee is responsible for ensuring that exposure to commodity, currency and interest rate risk, as well as marketing, trading and hedging practices, are monitored within the framework established by our company policies. The committee also is responsible for ensuring that marketing and hedging strategies are developed and implemented to mitigate or manage those risks within acceptable risk thresholds.

In certain cases, a Board committee is responsible for oversight of specific risk topics. For example, the Audit Committee oversees risk issues associated with our overall financial reporting and disclosure process and legal compliance, as well as

reviewing policies and procedures on risk-control assessment and accounting-risk exposure, including our companywide risk control activities and our business continuity and disaster-recovery plans. The Audit Committee meets with our Chief Financial Officer and General Counsel, and meets with our Vice President – Audit Services, as well as with our independent registered public accounting firm, in separate executive sessions at each of its in-person meetings during the year at which time risk issues are discussed regularly.

In addition, our Executive Compensation Committee oversees risks related to our compensation program, as discussed in greater detail elsewhere in this proxy statement, and our Corporate Governance Committee oversees risks related to our governance practices and policies.

BOARD AND COMMITTEE MEMBERSHIP

Our business, property and affairs are managed under the direction of our Board of Directors. Members of our Board are kept informed of our business through discussions with our Chief Executive Officer and other officers, by reviewing materials provided to them periodically and in connection with Board and committee meetings, by visiting our offices and our operating facilities and by participating in meetings of the Board and its committees.

During 2015, the Board held eight regular meetings and nine special meetings. All of our incumbent directors who served on the Board during 2015 attended at least 75 percent of the aggregate of all meetings of the Board and Board committees on which they served in 2015.

Our corporate governance guidelines provide that members of our Board are expected to attend our annual meeting of shareholders. All members of our Board attended our 2015 annual meeting of shareholders.

The Board has four standing committees consisting of the Audit Committee, the Executive Compensation Committee, the Corporate Governance Committee and the Executive Committee.

The table below provides the current membership of our Board and each of our Board committees.

Our Board has adopted written charters for each of its Audit, Executive Compensation, Corporate Governance and Executive Committees. Copies of the charters of each of these committees are available on and may be printed from our website at www.oneok.com. Copies are also available from our corporate secretary upon request. The responsibilities of our Board committees are summarized below. From time to time the Board, in its discretion, may form other committees.

The Audit Committee. The Audit Committee represents and assists our Board of Directors with the oversight of the integrity of our financial statements and internal control over financial reporting, our compliance with legal and regulatory requirements, the independence, qualifications and performance of our independent registered public accounting firm and the performance of our internal audit function. The responsibilities of the Audit Committee include:

Our independent registered public accounting firm reports directly to our Audit Committee.

All members of our Audit Committee are “independent” under the independence requirements of the NYSE and the Securities and Exchange Commission applicable to audit committee members. The Board has determined that James C. Day, Julie H. Edwards, Gary D. Parker, Brian L. Derksen and Randall J. Larson are each an audit committee financial expert under the applicable rules of the Securities and Exchange Commission.

The Audit Committee held six regular meetings in 2015.

The Executive Compensation Committee. Our Executive Compensation Committee is responsible for establishing and periodically reviewing our executive compensation policies and practices. This responsibility includes:

Our Executive Compensation Committee meets periodically during the year to review our executive and director compensation policies and practices. Executive officer salaries and short- and long-term incentive compensation are determined annually by this committee. The scope of the authority of this committee is not limited except as set forth in its charter and by applicable law. This committee has the authority to delegate duties to subcommittees of this committee, or to other standing committees of the Board of Directors, as it deems necessary or

appropriate. This committee may not delegate to a subcommittee any authority required by any law, regulation or listing standard to be exercised by this committee as a whole.

All members of our Executive Compensation Committee are “independent” under the independence requirements of the NYSE applicable to compensation committee members.

The executive compensation group in our corporate human resources department supports, in consultation with our Chief Executive Officer, the Executive Compensation Committee in its work.

During 2015, the Executive Compensation Committee engaged Meridian Compensation Partners, LLC (“Meridian Compensation Partners”), as an independent executive compensation consultant to assist the committee in its evaluation of the amount and form of compensation paid in 2015 to our Chief Executive Officer, our other executive officers and our directors. Meridian Compensation Partners reported directly to the Executive Compensation Committee. For more information on executive compensation and the role of this consultant, see “Executive Compensation Discussion and Analysis – Compensation Methodology – The Role of the Independent Executive Compensation Consultant” at page 60.

The Executive Compensation Committee held four regular meetings in 2015.

The Corporate Governance Committee. Our Corporate Governance Committee is responsible for overseeing our company’s governance, including the selection of directors and the Board’s practices and effectiveness. These responsibilities include:

All members of our Corporate Governance Committee are “independent” under the independence requirements of the NYSE.

The Corporate Governance Committee held three regular meetings and one special meeting in 2015.

The Executive Committee. In the intervals between meetings of our Board of Directors, the Executive Committee may, except as otherwise provided in our By-laws and applicable law, exercise the powers and authority of the full Board in the oversight of our property, affairs and business. The function of this committee is to act on major matters where it deems action appropriate, which provides a degree of flexibility and ability to respond to time-sensitive business and legal matters without calling a special meeting of our full Board. The Executive Committee reports to the Board at its next meeting on any actions taken by the committee.

The Executive Committee held no meetings in 2015.

DIRECTOR NOMINATIONS

Our corporate governance guidelines provide that the Board of Directors is responsible for selecting candidates for Board membership and delegates the screening process to the Corporate Governance Committee of the Board. This committee, with recommendations and input from our Chairman of the Board, our Chief Executive Officer and members of our Board, evaluates the qualifications of each director candidate and assesses the appropriate mix of skills, qualifications and characteristics required of Board members in the context of the perceived needs of the Board at a given point in time. The committee is responsible for recommending to the full Board

candidates for nomination by the Board for election as members of our Board.

Our corporate governance guidelines provide that candidates for nomination by the Board must be committed to devoting the time and effort necessary to be productive members of the Board and that, in nominating candidates, the Board will endeavor to establish director diversity in personal background, race, gender, age and nationality. The guidelines also provide that the Board will seek to maintain a mix that includes, but is not limited to, the following areas of core competency: accounting and finance; investment banking; business judgment; management; energy industry knowledge; operations; leadership; strategic vision; law; and corporate relations.

The Corporate Governance Committee’s charter provides that it has the responsibility, in consultation with the Chairman of the Board and the Chief Executive Officer, to search for, recruit, screen, interview and select candidates for the position of director as necessary to fill vacancies on the Board or the additional needs of the Board and to consider management and shareholder recommendations for candidates for nomination by the Board. In carrying out this responsibility, the Corporate Governance Committee evaluates the qualifications and performance of incumbent directors and determines whether to recommend them for re-election to the Board. In addition, this committee determines, as necessary, the portfolio of skills, experience, diversity, perspective and background required for the effective functioning of the Board considering our business strategy and our regulatory, geographic and market environments.

Our corporate governance guidelines contain a policy regarding the Corporate Governance Committee’s consideration of prospective director candidates recommended by shareholders for nomination by our Board. Under this policy, any shareholder who wishes to recommend a prospective candidate for nomination by our Board for election at our 2017 annual meeting should send a letter of recommendation to our corporate secretary at our principal executive offices by no later than September 30, 2016. The letter should include the name, address and number of shares owned by the recommending shareholder (including, if the recommending shareholder is not a

shareholder of record, proof of ownership of the type referred to in Rule 14a-8(b)(2) of the proxy rules of the Securities and Exchange Commission), the prospective candidate’s name and address, a description of the prospective candidate’s background, qualifications and relationships, if any, with our company and all other information necessary for our Board to determine whether the prospective candidate meets the independence standards under the rules of the NYSE and our director independence guidelines. A signed statement from the prospective candidate should accompany the letter of recommendation indicating that he or she consents to being considered as a nominee of the Board and that, if nominated by the Board and elected by the shareholders, he or she will serve as a director. The committee will evaluate prospective candidates recommended by shareholders for nomination by our Board in light of the various factors set forth above.

Neither the Corporate Governance Committee, nor the Board, nor our company itself discriminates in any way against prospective candidates for nomination by the Board on the basis of age, sex, race, religion, or other personal characteristics. There are no differences in the manner in which the Corporate Governance Committee or the Board evaluates prospective candidates based on whether the prospective candidate is recommended by a shareholder or by the Corporate Governance Committee, provided that the recommending shareholder furnishes to our company a letter of recommendation containing the information described above along with the signed statement of the prospective candidate referred to above.

In addition to having the ability to recommend prospective candidates for nomination by our Board, under our By-laws, shareholders may themselves nominate candidates for election at an annual meeting of shareholders so long as they are shareholders of record when they give the notice described below and on the record date for the relevant annual meeting. Any shareholder who desires to nominate candidates for election as directors at our 2017 annual meeting must follow the procedures set forth in our By-laws. Under these procedures, notice of a shareholder nomination for the election of a director must be received by our corporate secretary at our principal executive offices not less than 120 calendar days before the first anniversary of the date that our proxy statement was released to

shareholders in connection with our 2016 annual meeting of shareholders (i.e., notice must be received no later than December 6, 2016). If the date of the 2017 annual meeting is more than 30 days after May 25, 2017, the first anniversary of our 2016 annual meeting, our corporate secretary must receive notice of a shareholder nomination by the close of business on the tenth day following the earlier of the day on which notice of the date of the 2017 annual meeting is mailed to shareholders or the day on which public announcement of the 2017 annual meeting date is made. In addition, in accordance with our By-laws, the shareholder notice must contain certain information about the candidate the shareholder desires to nominate for election as a director, the shareholder giving the notice and the beneficial owner, if any, on whose behalf the nomination is made.

DIRECTOR COMPENSATION

The Executive Compensation Committee reviews director compensation on an annual basis in consultation with the Committee’s independent compensation consultant, Meridian Compensation Partners. This review includes consideration of director compensation data compiled by Meridian for the same 17-company peer group used to assess competitive compensation for our executive officers in order to assess the competitive levels of compensation for our directors.

Compensation for each of our non-management directors for their service on our Board of Directors for the period of May 2014 through April 2015 and for the period May 2015 through April 2016 consisted of an annual cash retainer of $65,000 and a common stock annual retainer with a value of $135,000 determined using the average of the high and low trading prices of our company’s common stock on the NYSE on the date of the meeting of the Board of Directors immediately following the company’s annual shareholders meetings. The chairs of our Audit and Executive Compensation Committees received an additional annual cash retainer of $15,000, and our lead director, who is also chair of our Corporate Governance Committee, received an additional annual cash retainer of $20,000. Our non-executive Chairman of the Board received an additional annual cash retainer of $125,000 for his service.

All directors are reimbursed for reasonable expenses incurred in connection with attendance at Board and committee meetings.

Our one management director, Terry K. Spencer, receives no compensation for his service as a director.

Our Board of Directors has established minimum share ownership guidelines for members of our Board that are

discussed under “Executive Compensation Discussion and Analysis – Share Ownership Guidelines” at page 71.

The following table sets forth the compensation paid to our non-management directors in 2015.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

During 2015, Messrs. Mackie, Malcolm, Mogg, Rodriguez and Ms. Moore served on our Executive Compensation Committee. Mr. McCarthy has served on this committee since his election to our board on December 29, 2015. No member of the Executive Compensation Committee was an officer or employee of the company or any of its subsidiaries during 2015, and no member of this committee was formerly an officer of the company or any of its subsidiaries. In addition, during 2015, none of our executive officers served as a member of a compensation committee or board of directors of any other entity of which any member of our Board was an executive officer.

EXECUTIVE SESSIONS OF THE BOARD

The non-management members and independent members of our Board of Directors meet in separate, regularly scheduled executive sessions during each regular in-person meeting of the Board held during the year. We intend to continue this practice of regularly scheduled separate meetings of the non-management members and independent members of our Board. Our corporate governance guidelines provide that our lead independent director, who is the chair of our Corporate Governance Committee, presides as the chair at executive session meetings of the independent members of our Board.

COMMUNICATIONS WITH DIRECTORS

Our Board believes that it is management’s role to speak for our company. Directors refer all inquiries regarding our company from institutional investors, analysts, the news media, customers or suppliers to our Chief Executive Officer or his designee. Our Board also believes that any communications between members of the Board and interested parties, including shareholders, should be conducted with the knowledge of our Chief Executive Officer. Interested parties, including shareholders, may contact one or more members of our Board, including non-management directors and non-management directors as a group, by writing to the director or directors in care of our corporate secretary at our principal executive offices. A communication received from an interested party or shareholder will be forwarded promptly to the director or directors to whom the communication is addressed. A copy of the communication also will be provided to our Chief

Executive Officer. We will not, however, forward sales or marketing materials, materials that are abusive, threatening or otherwise inappropriate, or correspondence not clearly identified as interested party or shareholder correspondence.

COMPLAINT PROCEDURES

Our Board of Directors has adopted procedures for the receipt, retention and treatment of complaints regarding accounting, internal accounting controls, or auditing matters and complaints or concerns under our Code of Business Conduct and Ethics. These procedures allow for the confidential and anonymous submission by employees of concerns regarding questionable accounting or auditing matters and matters arising under our Code of Business Conduct and Ethics. The full text of these procedures, known as our whistleblower policy, is published on and may be printed from our website at www.oneok.com and is also available from our corporate secretary upon request.

ONEOK is the sole general partner of ONEOK Partners, L.P., one of the largest publicly traded master limited partnerships engaged in the natural gas gathering and processing, natural gas liquids and natural gas pipelines businesses. As we have evolved from a traditional natural gas distributor into a pure-play general partner of ONEOK Partners, we have maintained our focus on our stakeholders and our mission to provide management and resources to ONEOK Partners enabling it to operate in a safe, reliable and environmentally responsible manner. As we have grown our business and expanded our operational footprint over the last several years, we also have strengthened our commitment to improve our companywide environmental, safety and health (ESH) performance.

SAFETY AND HEALTH

The safety of our employees, customers and communities where we operate is at the forefront of each business decision we make. By monitoring the integrity of our assets and promoting the safety and health of our employees, customers and communities, we are investing in the long-term sustainability of our businesses.

We continuously assess the risks our employees face in their jobs, and we work to mitigate those risks through training, appropriate engineering controls, work procedures and other preventive safety and health programs. Reducing incidents and improving our safety incident rates is important, but we are not focused only on statistics. Low incident rates alone cannot prevent a large-scale incident, which is why we continue to focus on enhancing our process safety programs, such as near-miss reporting, risk assessment and others.

We are committed to pursuing a zero-incident safety culture by continuously working toward mitigating risk and eliminating incidents that may bring harm to our employees, contractors, the public and the environment. In order to achieve our corporate and operating ESH goals, it is our expectation that:

Contractor Safety

We expect and require our contractors to maintain the same high ESH performance standards we ask of our employees.

Because we use third-party contractors to assist in the construction, operation and maintenance of our facilities and assets, contractor management is an important element of our ESH management systems. As part of the management system, we have established contractor qualification, selection and retention criteria designed to attract the most qualified companies. Each company we contract with is responsible for providing personnel who are appropriately screened, trained, qualified and are able to perform specified duties related to all ESH policies and procedures. Once selected, contractors are monitored periodically to ensure they are in compliance with our ESH expectations.

In 2014, our construction projects team implemented a new tool, Safety Tracking for ONEOK Major Projects (STOMP), designed to

capture and monitor large project contractors’ ESH performance. The statistical data from this tool will enhance current and future contractor selection and also allow us to track, year over year, the safety performances of our contractors.

We believe an effective contractor safety program enhances our projects by assisting contractors with systematically identifying and evaluating anticipated hazards and establishing controls in advance of actual work.

Asset Management

It is always our goal to ensure we operate our assets safely, reliably and environmentally responsibly.

Asset integrity is the ability of an asset to perform its required function effectively and efficiently while also protecting those that live and work near our facilities and the environment. We maintain mature programs that guide trained staff in the completion of these activities, and we continue to enhance and improve these programs and our internal capabilities.

While many of our assets are regulated by local, state and federal agencies, our activities are not limited to compliance. Asset integrity is critical in many ways, and our programs and people are dedicated to satisfying the expectations of each of our key stakeholders, including governmental regulatory agencies, the communities in which we operate, landowners, our customers, our employees and investors.

Facility Integrity. Our risk-based inspection program is a data-intensive engineering analysis using information from design, construction, operation and inspection processes to ensure our above ground fixed equipment is appropriately maintained, its current condition is known, and it is operated within safe limits.

Pipeline Integrity. Our pipeline integrity management program has been developed to meet or exceed state and federal regulatory requirements for pipeline safety and is further strengthened by participation in industry-level program improvement initiatives.

This program provides guidance for identification of high consequence areas and threats specific to individual pipeline segments. Appropriate inspection methods and threat prevention or mitigation activities are selected and scheduled

based on a process of integrity-related integration and evaluation, with a new evaluation cycle starting with the completion of the current cycle.

Underground Storage Integrity. Our underground storage safety management program guides our engineering and operations staff in the inspection, maintenance and remediation of storage assets.

Reservoirs, mined salt caverns and mined rock caverns are used to store natural gas, natural gas liquids and certain refined products within a regulatory and industry appropriate framework. This type of storage is used to protect the community, preserve the product inventory and maintain and develop storage assets. This specialized, technical field depends heavily on industry best practices, experienced practitioners and rigorous documentation and recordkeeping.

Safety and Health Highlights and Awards

ENVIRONMENTAL PERFORMANCE

We continue to focus on being environmentally responsible while operating our assets safely and reliably. Because of the nature of our business, maintaining accurate emissions records and complying with regulatory reporting guidelines continues to be of primary importance to us. A number of emission-reduction efforts have been implemented across our operations in recent years, and we continue to look for new ways to improve our environmental stewardship.

Our long-standing commitment to being good stewards of the environment is defined by our corporate environmental practices. We recognize climate change is an important environmental issue and that reduced greenhouse gas (GHG) emissions play a role in minimizing potential effects on our environment.

Maintaining accurate GHG emissions records and complying with all regulatory reporting guidelines are central to our continued environmental initiatives. Our environmental compliance efforts strive to create responsible processes for managing environmental risks.

Environmental compliance requires adherence to laws and regulations. Our goal is environmental excellence – operating our businesses to meet the various expectations of each of our key stakeholders, including the regulatory agencies as well as the communities in which we operate, landowners, our customers, our employees and investors.

Greenhouse Gas Emissions

In 2010, we began reporting our annual GHG emissions for our facilities which have the potential to emit at or above 25,000 metric tons of carbon dioxide equivalents per year, in accordance with standards set by the Environmental Protection Agency (EPA) under the Federal Clean Air Act, as amended. Carbon dioxide equivalent (CO₂e) is a metric used to compare the emissions from various GHGs based on their global-warming potential. It is determined by multiplying the tons of a specific GHG by its associated global warming potential factor.

Through this program, we report specific information to the EPA, including:

Based on threshold levels in 2015, we reported emissions from 27 facilities totaling approximately 47.8 million metric tons of CO₂e. Of these emissions, approximately 1.9 million metric tons of CO₂e—or 4%—were directly attributable to our operations. The remaining emissions reported represent estimated emissions from the products we deliver to our customers.

We endeavor to reduce all emissions at our facilities that can result from natural gas combustion for certain components of our

operations, equipment leaks and other processes common to natural gas systems.

In 2015, specific efforts by ONEOK Partners related to methane emissions included:

Carbon Disclosure Project

In 2015, we participated in the Carbon Disclosure Project (CDP) for the third consecutive year. The CDP is an international organization that works with shareholders and corporations to disclose the carbon emissions of participating companies. In

2015, the CDP received carbon data from more than 5,000 companies worldwide. For the second consecutive year our CDP score improved significantly from the prior year. We expect to continue our participation in the CDP.

Short-Term Incentive Environmental Metric

In 2014, we created a new incentive compensation metric for inclusion in our short-term incentive plan that measures our environmental performance by tracking releases and other emission events that must be reported to regulatory agencies. While we have measured the number of agency-reportable spills and releases since 2008, the AREER metric is a subset of that measure. After giving effect to updates made by the Committee in 2015, AREER is defined as the total number of releases and excess emission events that trigger a federal, state or local environmental-reporting requirement (with some exceptions to account for events outside of our control, planned maintenance and disparities in reporting requirements across our operations), divided by the applicable number of “capacity units” (miles of pipelines, natural gas liquids storage capacity, natural gas storage capacity, natural gas liquids fractionation capacity, and natural gas processing capacity). In 2015, a sixth component was added to the definition of “capacity units” to account for growth in pipeline pump/compressor stations. Also in 2015, the relative weighting of the six components was adjusted to more accurately reflect the risk of environmental events in the various asset types as identified in those events we experienced in 2014.

Although the AREER metric is only two years old, it has been effective in driving improved environmental performance. Our 2015 AREER was a 48% reduction from a normalized 2014 value.

COMMUNITY INVESTMENTS

We are committed to being active members of the communities where we operate. Investing in the areas where we have operations and where our employees live and work is not only the right thing to do – it is smart business. By contributing financially and through volunteer work, we can help build stronger communities and create a better environment for our employees, customers and the general public.

We accomplish this in a number of ways, including grants from the ONEOK Foundation, Inc., corporate contributions to nonprofit organizations and by community volunteer efforts. Primary focus

areas for our community investments are education, health and human services, environmental, arts and culture, and community improvement. We give priority consideration to educational programs and to health and human services organizations, particularly those with programs that help people become self-sufficient.

2015 Community Investments Updates and Highlights

In 2015, the ONEOK Foundation, Inc. contributed approximately $3.4 million and ONEOK made corporate contributions of approximately $1.9 million to support local nonprofit organizations. In 2015, our employees volunteered more than 4,490 hours in our communities, with a value of approximately $101,274 (based on the current volunteer-hour value of $22.55).

POLITICAL ADVOCACY AND CONTRIBUTIONS

We actively participate in the political process through the lobbying efforts of our government relations department, involvement in multiple business and industry trade organizations, and through the ONEOK, Inc. Employee Political Action Committee (ONEOK PAC).

Political contributions to federal, state and local candidates are made by the ONEOK PAC which is funded by voluntary contributions from eligible company employees. The ONEOK PAC’s activities are guided by a steering committee comprised of senior management and a contribution committee comprised of ONEOK PAC members and are subject to comprehensive regulation, including detailed disclosure requirements. ONEOK PAC contributions are reported to the Federal Election Commission and applicable state regulatory authorities. During 2015, the ONEOK PAC made contributions to state and federal candidates for office in the amount of $53,790. We also paid $393,000 to state and federal contract lobbyists.

We belong to a number of industry associations that participate in the political process. Industry associations promote collaboration between companies within an industry concerning public policy initiatives and represent industry interests in the legislative and regulatory arenas. Our sole purpose in becoming a member of these industry associations is not for political purposes, as we may not agree with all positions taken by industry associations on issues. The benefits that we receive from industry associations are primarily expertise and the ability to gain insight on industry

related matters. In 2015, we paid dues of approximately $625,000 to 44 trade and industry associations, of which approximately 26 percent was allocated by those associations to lobby expenses and political expenditures.

As a company, we do not contribute corporate funds to political candidates, political action committees or so-called 501(c)(4) social welfare organizations.

Our lobbying and political activities are reviewed annually by the Board of Directors. We believe this oversight process ensures accountability and transparency for our lobbying and political activities.

BOARD REFRESHMENT

Our Board recognizes the importance of Board refreshment to help ensure an appropriate balance of experience, expertise and perspective on our Board. During 2015 our By-laws and corporate governance guidelines provided for mandatory director retirement upon a director reaching age 73. Consistent with this requirement, two of our board members retired from our Board in 2015. Our By-laws and corporate governance guidelines were revised in early 2016 to provide that a director will retire from the Board no later than immediately prior to the annual meeting of shareholders following a director’s 73rd birthday. In accordance with these revised provisions, a third director, Mr. James C. Day, will retire from the Board immediately prior to our annual meeting of shareholders on May 25, 2016.

In anticipation of these retirements, in 2015 our Corporate Governance Committee considered several qualified board candidates identified by members of our Board and, on December 29, 2015, based on the recommendation of the Committee, our Board elected Kevin S. McCarthy, Randall J. Larson and Brian L. Derksen to our Board. These new board members add to the Board’s experience, expertise and knowledge in a number of areas, including natural gas and natural gas liquids gathering, processing, transportation and storage operations and accounting and finance in the midstream sector of the energy industry. Your Board of Directors believes that these new directors, along with our incumbent directors, reflect a balanced Board with deep experience and diverse expertise.

The average age of our 12 current board members is 62 and the average tenure of a board member is 7.4 years.

ANNUAL ELECTION BY MAJORITY VOTE

Our certificate of incorporation provides for the annual election of directors. Our Board of Directors currently consists of 12 members, each of whose terms will expire at the 2016 annual meeting. In accordance with our By-laws and corporate governance guidelines, Mr. Day will retire from the Board immediately preceding our 2016 annual meeting of shareholders on May 25, 2016. Accordingly, the remaining 11 current members of our Board of Directors named in this proxy statement will stand for re-election at the annual meeting.

In addition, as more fully described above, our By-laws provide for majority voting for directors in uncontested elections and our corporate governance guidelines require that a nominee for director who does not receive the requisite majority vote in an uncontested election must promptly tender his or her resignation to our Board of Directors for its consideration.

The persons named in the accompanying proxy card intend to vote such proxy in favor of the election of each of the nominees named below, who are all currently directors, unless the proxy provides for a vote against the director. Although the Board has no reason to believe that the nominees will be unable to serve as directors, if a nominee withdraws or otherwise becomes unavailable to serve, the persons named as proxies will vote for any substitute nominee designated by the Board, unless contrary instructions are given on the proxy. Except for these nominees, no other person has been recommended to our Board as a potential nominee or otherwise nominated for election as a director.

BOARD QUALIFICATIONS

Our corporate governance guidelines provide that our Corporate Governance Committee will evaluate the qualifications of each director candidate and assess the appropriate mix of skills and characteristics required of board members in the context of the perceived needs of the Board at a given point in time. Each director also is expected to:

Director Diversity and Core Competencies

Our governance guidelines provide that, in nominating candidates, the Board will endeavor to establish director diversity in personal background, race, gender, age and nationality, and to maintain a mix that includes, but is not limited to, the following

areas of core competency: accounting and finance; investment banking; business judgment; management; energy industry knowledge; operations; leadership; strategic vision; law; and corporate relations.

Your Board of Directors believes that each member of our Board possesses the necessary integrity, skills and qualifications to serve on our Board and that their individual and collective skills and qualifications provide them with the ability to engage management and each other in a constructive and collaborative fashion and, when necessary and appropriate, challenge management in the execution of our business operations and strategy.

RATIFICATION OF SELECTION OF

PRICEWATERHOUSECOOPERS LLP AS OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR 2016

The Audit Committee has the sole authority and responsibility to hire, evaluate and, where appropriate, replace the company’s independent auditor and, in its capacity as a committee of our Board of Directors, is directly responsible for the appointment, compensation and general oversight of the work of the independent auditor. The Audit Committee is responsible for approving the audit and permissible non-audit services provided by the independent auditor and the associated fees.

The Audit Committee evaluates the performance of our independent auditor, including the senior audit engagement team, each year and determines whether to re-engage the current independent auditor or consider other audit firms. In doing so, the Audit Committee considers the quality and efficiency of the services provided by the auditors, the auditors’ capabilities and the auditors’ technical expertise and knowledge of our operations and industry. In connection with the mandated rotation of the independent auditor’s lead engagement partner, the Audit Committee and its chairperson are directly involved in the selection of the new lead engagement partner.

Based on this evaluation, the Audit Committee has appointed PricewaterhouseCoopers LLP to serve as our independent auditor for the fiscal year ending December 31, 2016. PricewaterhouseCoopers LLP has served as our independent auditor for nine years and is considered by management to be well qualified. Further, the Audit Committee and the Board of Directors believe that the continued retention of PricewaterhouseCoopers LLP to serve as our independent auditor is in the best interests of the company and its shareholders.

Our Board of Directors has ratified the selection by our Audit Committee of PricewaterhouseCoopers LLP to serve as our

independent (consistent with Securities and Exchange Commission and NYSE policies regarding independence) registered public accounting firm for 2016. As a matter of good corporate governance, the Audit Committee submits its selection of our independent auditor to our shareholders for ratification. If the shareholders should not ratify the appointment of PricewaterhouseCoopers LLP, the Audit Committee will reconsider the appointment.

In carrying out its duties in connection with the 2015 audit, PricewaterhouseCoopers LLP had unrestricted access to our Audit Committee to discuss audit findings and other financial matters. Representatives of PricewaterhouseCoopers LLP will be present at the annual meeting to answer questions. They also will have the opportunity to make a statement if they desire to do so.

Approval of this proposal to ratify the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm requires the affirmative vote of a majority of the voting power of the shareholders present in person or by proxy and entitled to vote on this proposal at the meeting. Abstentions will have the effect of a vote against the proposal.

Your Board unanimously recommends a vote FOR the ratification of the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm for 2016.

AUDIT AND NON-AUDIT FEES

Audit services provided by PricewaterhouseCoopers LLP during the 2015 and 2014 fiscal years included an integrated audit of our consolidated financial statements and internal control over financial reporting, review of our unaudited quarterly financial statements, consents and review of documents filed with the Securities and Exchange Commission, and performance of certain agreed-upon procedures.

AUDIT COMMITTEE POLICY ON SERVICES PROVIDED BY THE INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

Consistent with Securities and Exchange Commission and NYSE policies regarding auditor independence, the Audit Committee has the responsibility for appointing, setting compensation and overseeing the work of our independent auditor. In furtherance of this responsibility, the Audit Committee has established a policy with respect to the pre-approval of audit and permissible non-audit services provided by our independent auditor.

Prior to engagement of PricewaterhouseCoopers LLP as our independent auditor for the 2016 audit, a plan was submitted to and approved by the Audit Committee setting forth the audit services expected to be rendered during 2016, which are comprised of work performed in the audit of our financial statements and to attest and report on our internal controls over financial reporting, as well as work that only the independent auditor can reasonably be expected to provide, including quarterly review of our unaudited financial statements, comfort letters, statutory audits, attest services, consents and assistance with the review of documents filed with the Securities and Exchange Commission.

The Audit Committee has adopted a policy that provides that fees for audit, audit related and tax services that are not included in the

independent auditor’s annual services plan, and for services for which fees are not determinable on an annual basis, are pre-approved if the fees for such services will not exceed $75,000. In addition, the policy provides that the Audit Committee may delegate pre-approval authority to one or more of its members. The member to whom such authority is delegated must report, for informational purposes only, any pre-approval decisions to the Audit Committee at its next scheduled meeting.

2016 REPORT OF THE AUDIT COMMITTEE

The purpose of the Audit Committee is to assist the Board of Directors with the oversight of the integrity of the company’s financial statements and internal control over financial reporting, the company’s compliance with legal and regulatory requirements, the independence, qualifications and performance of the company’s independent registered public accounting firm and the performance of the company’s internal audit function. The Audit Committee’s function is more fully described in its charter, which the Board reviews and approves on an annual basis. The charter is on and may be printed from the company’s website at www.oneok.com and is also available from the company’s corporate secretary upon request. The Board of Directors annually reviews the definition of “independence” for audit committee members contained in the listing standards for the NYSE and applicable rules of the Securities and Exchange

Commission, as well as our director independence guidelines, and has determined that each member of the Audit Committee is independent under those standards.

Management is responsible for the preparation, presentation and integrity of the company’s financial statements, accounting and financial reporting principles, internal controls and procedures designed to ensure compliance with accounting standards, applicable laws and regulations. The company’s independent registered public accounting firm, PricewaterhouseCoopers LLP, is responsible for performing an independent audit of the company’s consolidated financial statements and the company’s internal control over financial reporting and expressing an opinion on the conformity of those financial statements with generally accepted accounting principles and on the effectiveness of the company’s internal control over financial reporting.

In this context, the Audit Committee has met and held discussions with management and the company’s independent registered public accounting firm, PricewaterhouseCoopers LLP, regarding the fair and complete presentation of the company’s financial results and management’s report on its assessment of the company’s internal control over financial reporting. The Audit Committee has discussed the significant accounting policies applied by the company in its financial statements, as well as alternative treatments. Management has represented to the Audit Committee that the company’s consolidated financial statements were prepared in accordance with generally accepted accounting principles, and the Audit Committee has reviewed and discussed the consolidated financial statements with management and the independent auditor.

The Audit Committee has also reviewed and discussed with both management and the independent registered public accounting firm management’s assessment of the company’s internal control over financial reporting. In addition, the Audit Committee has discussed the independent auditor’s report on the company’s internal control over financial reporting. The Audit Committee has also discussed with the company’s independent auditor the matters required to be discussed by Public Company Accounting Oversight Board (United States) Auditing Standard No. 16, Communications with Audit Committees, and Rule 2-07 of the

Securities and Exchange Commission’s Regulation S-X (“Communication with Audit Committees”).

In addition, the Audit Committee has discussed with the independent registered public accounting firm the firm’s independence from the company and its management, including the matters in the written disclosures and the letter received from PricewaterhouseCoopers LLP as required by the applicable requirements of the Public Company Accounting Oversight Board (United States) regarding the independent accountant’s communications with the Audit Committee concerning independence. While non-audit services provided by PricewaterhouseCoopers LLP were not significant in 2014 or 2015, the Audit Committee will also consider in the future whether the provision of non-audit services to the company by PricewaterhouseCoopers LLP is compatible with maintaining that firm’s independence. The Audit Committee has concluded that the independent registered public accounting firm is independent from the company and its management.

The Audit Committee discussed with the company’s internal and independent auditors the overall scope and plans for their respective audits. The Audit Committee meets with both the internal and independent auditors, with and without management present, to discuss the results of their examinations, the assessments of the company’s internal control over financial reporting and the overall quality of the company’s financial reporting. Based on the review and discussions referred to above, the Audit Committee recommended to the Board of Directors, and the Board of Directors approved, the inclusion of the audited financial statements of the company as of and for the year ended December 31, 2015, in the company’s Annual Report on Form 10-K for the year ended December 31, 2015, for filing with the Securities and Exchange Commission.

Respectfully submitted by the members of the Audit Committee of the Board of Directors:

Julie H. Edwards, Chair

Gary D. Parker, Vice Chair

James C. Day, Member

Brian L. Derksen, Member

Randall J. Larson, Member

HOLDINGS OF OFFICERS AND DIRECTORS

The following table sets forth the number of shares of our common stock and the number of common units of our affiliate, ONEOK Partners, beneficially owned as of February 1, 2016, by (1) each director and nominee for director, (2) each of the

executive officers named in the Summary Compensation Table for Fiscal 2015 under the caption “Executive Compensation Discussion and Analysis” in this proxy statement, and (3) all directors and executive officers as a group.