UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549

                                    Form 13F

                              FORM 13F COVER PAGE

Report for the Calendar Year or Quarter Ended:  September 30, 2010

Check here if Amendment [  ]; Amendment Number:
This Amendment (Check only one):  [  ] is a restatement.
                                  [  ]  adds new holdings entries.

Institutional Investment Manager Filing this Report:

Name:     Hennessy Advisors, Inc.
Address:  7250 Redwood Boulevard, Suite 200
          Novato, CA  94945

Form 13F File Number:  028-06715

The institutional investment manager filing this report and the person by whom
it is signed hereby represent that the person signing the report is authorized
to submit it, that all information contained herein is true, correct and
complete, and that it is understood that all required items, statements,
schedules, lists, and tables, are considered integral parts of this form.

Person Signing this Report on Behalf of Reporting Manager:

Name:    Teresa M. Nilsen
Title:   Executive Vice President and Chief Financial Officer
Phone:   (415) 899-1555

Signature, Place, and Date of Signing:

/s/ Teresa M. Nilsen              Novato, CA                   October 25, 2010
--------------------------------------------------------------------------------
Teresa M. Nilsen                  City, State                      Date

Report Type  (Check only one):

[X]   13F HOLDINGS REPORT.  (Check here if all holdings of this reporting
      manager are reported in this report.)

[  ]  13F NOTICE.  (Check here if no holdings reported are in this report,
      and all holdings are reported by other reporting manager(s).)

[  ]  13F COMBINATION REPORT.  (Check here if a portion of the holdings for
      this reporting manager are reported in this report and a portion are
      reported byother reporting manager(s).)


                             FORM 13F SUMMARY PAGE


Report Summary:


Number of Other Included Managers:                0
                                         -------------
Form 13F Information Table Entry Total:         216
                                         -------------
Form 13F Information Table Value Total:    $651,605
                                         -------------
                                          (thousands)


List of Other Included Managers:     NONE



                                                        FORM 13F INFORMATION TABLE

                                         Name of Reporting Manager: Hennessy Advisors, Inc.

                                                           Value   Shares/  Sh/ Put/ Invstmt    Other          Voting Authority
        Name of Issuer         Title of Class     CUSIP   (x1000)  Prn Amt  Prn Call Dscretn   Managers     Sole    Shared   None
------------------------------ ---------------- --------- -------- -------- --- ---- ------- ------------ -------- -------- -------
                                                                                                 
ACERGY S A                     SPONSORED ADR    00443E104   4,421   239,600  SH      SOLE                 239,600
ADVANCE AMER CASH ADVANCE      COM              00739W107   2,485   616,630  SH      SOLE                 616,630
ADVANCE AUTO PARTS INC         COM              00751Y106   4,336    73,900  SH      SOLE                  73,900
ADVANCED MICRO DEVICES INC     COM              007903107   3,578   503,200  SH      SOLE                 503,200
AIR TRANSPORT SERVICES GRP INC COM              00922R105     652   107,000  SH      SOLE                 107,000
ALAMO GROUP INC                COM              011311107     556    24,900  SH      SOLE                  24,900
ALASKA AIR GROUP INC           COM              011659109     602    11,800  SH      SOLE                  11,800
ALLIED HEALTHCARE INTL INC     COM              01923A109      28    11,090  SH      SOLE                  11,090
ALTRIA GROUP INC               COM              02209S103   5,304   220,800  SH      SOLE                 220,800
AMERICAN AXLE & MFG HLDGS INC  COM              024061103   4,774   529,300  SH      SOLE                 529,300
AMERICAN INTL GROUP INC        COM              026874784     594    15,200  SH      SOLE                  15,200
AMERICREDIT CORP               COM              03060R101   4,794   196,000  SH      SOLE                 196,000
AMERIGROUP CORP                COM              03073T102   4,757   112,000  SH      SOLE                 112,000
APOLLO GROUP INC               COM              037604105   1,232    24,000  SH      SOLE                  24,000
APPLIED INDL TECHNOLOGIES INC  COM              03820C105   4,443   145,200  SH      SOLE                 145,200
ARVINMERITOR INC               COM              043353101   5,223   336,100  SH      SOLE                 336,100
AT&T INC                       COM              00206R102   8,177   285,900  SH      SOLE                 285,900
AUTOLIV INC                    COM              052800109   4,625    70,800  SH      SOLE                  70,800
AUTOMATIC DATA PROCESSING INC  COM              053015103   2,917    69,400  SH      SOLE                  69,400
AUTOZONE INC                   COM              053332102   1,877     8,200  SH      SOLE                   8,200
BANCO MACRO SA                 SPON ADR B       05961W105     806    18,100  SH      SOLE                  18,100
BAXTER INTL INC                COM              071813109   1,493    31,300  SH      SOLE                  31,300
BCE INC                        COM NEW          05534B760   3,686   113,400  SH      SOLE                 113,400
BECTON DICKINSON & CO          COM              075887109   1,452    19,600  SH      SOLE                  19,600
BEST BUY INC                   COM              086516101   1,307    32,000  SH      SOLE                  32,000
BIG 5 SPORTING GOODS CORP      COM              08915P101   2,976   221,730  SH      SOLE                 221,730
BOEING CO                      COM              097023105   4,558    68,500  SH      SOLE                  68,500
BORGWARNER INC                 COM              099724106   4,757    90,400  SH      SOLE                  90,400
BP PLC                         SPONSORED ADR    055622104   2,157    52,400  SH      SOLE                  52,400
BRASKEM S A                    SP ADR PFD A     105532105   5,116   249,200  SH      SOLE                 249,200
BRISTOL MYERS SQUIBB CO        COM              110122108   4,758   175,500  SH      SOLE                 175,500
BROWN SHOE INC NEW             COM              115736100     384    33,500  SH      SOLE                  33,500
BRUNSWICK CORP                 COM              117043109   5,211   342,400  SH      SOLE                 342,400
BUCYRUS INTL INC NEW           COM              118759109   4,841    69,800  SH      SOLE                  69,800
CALLON PETE CO DEL             COM              13123X102     452    91,300  SH      SOLE                  91,300
CALUMET SPECIALTY PRODS PTNRS  UT LTD PARTNER   131476103   3,812   193,300  SH      SOLE                 193,300
CAMPBELL SOUP CO               COM              134429109   4,698   131,400  SH      SOLE                 131,400
CARDINAL HEALTH INC            COM              14149Y108   1,374    41,600  SH      SOLE                  41,600
CARDTRONICS INC                COM              14161H108   5,467   354,300  SH      SOLE                 354,300
CARMAX INC                     COM              143130102   5,073   182,100  SH      SOLE                 182,100
CASCADE CORP                   COM              147195101     455    14,300  SH      SOLE                  14,300
CHEVRON CORP NEW               COM              166764100   8,616   106,300  SH      SOLE                 106,300
CHINA MOBILE LIMITED           SPONSORED ADR    16941M109   3,272    64,000  SH      SOLE                  64,000
CIGNA CORP                     COM              125509109   5,582   156,000  SH      SOLE                 156,000
CLEARWATER PAPER CORP          COM              18538R103     723     9,500  SH      SOLE                   9,500
CLOROX CO DEL                  COM              189054109   1,556    23,300  SH      SOLE                  23,300
COCA COLA CO                   COM              191216100   2,434    41,600  SH      SOLE                  41,600
COMMERCIAL VEH GROUP INC       COM              202608105     487    47,800  SH      SOLE                  47,800
COMPANHIA BRASILEIRA DE DIST   SPN ADR PFD CL A 20440T201   3,741    54,200  SH      SOLE                  54,200
COMPLETE PRODUCTION SERVICES   COM              20453E109   4,131   202,000  SH      SOLE                 202,000
CONAGRA FOODS INC              COM              205887102   2,911   132,700  SH      SOLE                 132,700
CONSOL ENERGY INC              COM              20854P109   1,268    34,300  SH      SOLE                  34,300
CONSOLIDATED GRAPHICS INC      COM              209341106     502    12,100  SH      SOLE                  12,100
COOPER COS INC                 COM              216648402   4,913   106,300  SH      SOLE                 106,300
COTT CORP QUE                  COM              22163N106   3,483   443,700  SH      SOLE                 443,700
CROCS INC                      COM              227046109   5,485   421,600  SH      SOLE                 421,600
CROWN HOLDINGS INC             COM              228368106   1,582    55,200  SH      SOLE                  55,200
DCP MIDSTREAM PARTNERS LP      COM              23311P100   4,904   146,400  SH      SOLE                 146,400
DIAGEO P L C                   SPON ADR NEW     25243Q205   2,974    43,100  SH      SOLE                  43,100
DIAMOND MGMT & TECHNOLOGY      COM              25269L106     639    51,100  SH      SOLE                  51,100
DIAMOND OFFSHORE DRILLING INC  COM              25271C102   1,193    17,600  SH      SOLE                  17,600
DIRECTV                        COM              25490A101   1,715    41,200  SH      SOLE                  41,200
DISH NETWORK CORP              COM              25470M109   1,293    67,500  SH      SOLE                  67,500
DOLLAR TREE INC                COM              256746108   6,178   126,700  SH      SOLE                 126,700
DONNELLEY R R & SONS CO        COM              257867101   2,308   136,100  SH      SOLE                 136,100
DOT HILL SYSTEMS CORP          COM              25848T109      24    17,310  SH      SOLE                  17,310
DRUGSTORE.COM INC              COM              262241102      21    10,700  SH      SOLE                  10,700
DU PONT E I DE NEMOURS & CO    COM              263534109   9,765   218,850  SH      SOLE                 218,850
DYNAVAX TECHNOLOGIES CORP      COM              268158102      36    19,840  SH      SOLE                  19,840
EATON CORP                     COM              278058102   3,836    46,500  SH      SOLE                  46,500
EMERSON ELEC CO                COM              291011104   3,707    70,400  SH      SOLE                  70,400
ENCORE CAP GROUP INC           COM              292554102   3,690   204,800  SH      SOLE                 204,800
ENI S P A                      SPONSORED ADR    26874R108   2,608    60,400  SH      SOLE                  60,400
ENTERPRISE GP HLDGS L P        COM              293716106     693    11,800  SH      SOLE                  11,800
ESTERLINE TECHNOLOGIES CORP    COM              297425100     630    11,000  SH      SOLE                  11,000
F M C CORP                     COM              302491303   1,594    23,300  SH      SOLE                  23,300
FAMILY DLR STORES INC          COM              307000109   6,068   137,400  SH      SOLE                 137,400
FERRO CORP                     COM              315405100   4,484   347,900  SH      SOLE                 347,900
FLOWSERVE CORP                 COM              34354P105   1,401    12,800  SH      SOLE                  12,800
FLUOR CORP NEW                 COM              343412102   1,412    28,500  SH      SOLE                  28,500
FORD MTR CO DEL                COM              345370860   4,990   407,700  SH      SOLE                 407,700
FOREST LABS INC                COM              345838106   1,701    55,000  SH      SOLE                  55,000
FREEPORT-MCMORAN COPPER & GO   COM              35671D857   1,665    19,500  SH      SOLE                  19,500
FRONTIER COMMUNICATIONS CORP   COM              35906A108     364    44,600  SH      SOLE                  44,600
GAP INC DEL                    COM              364760108   1,102    59,100  SH      SOLE                  59,100
GARDNER DENVER INC             COM              365558105     617    11,500  SH      SOLE                  11,500
GENCORP INC                    COM              368682100   2,152   437,300  SH      SOLE                 437,300
GENERAL MLS INC                COM              370334104   1,564    42,800  SH      SOLE                  42,800
GLAXOSMITHKLINE PLC            SPONSORED ADR    37733W105   2,782    70,400  SH      SOLE                  70,400
GLOBAL CASH ACCESS HLDGS INC   COM              378967103   1,996   489,200  SH      SOLE                 489,200
GSI COMMERCE INC               COM              36238G102   3,875   156,900  SH      SOLE                 156,900
HEALTHSPRING INC               COM              42224N101   4,840   187,300  SH      SOLE                 187,300
HEINZ H J CO                   COM              423074103   4,865   102,700  SH      SOLE                 102,700
HERSHEY CO                     COM              427866108   3,969    83,400  SH      SOLE                  83,400
HHGREGG INC                    COM              42833L108   4,335   175,100  SH      SOLE                 175,100
HILL ROM HLDGS INC             COM              431475102     646    18,000  SH      SOLE                  18,000
HOME DEPOT INC                 COM              437076102   7,176   226,500  SH      SOLE                 226,500
HONEYWELL INTL INC             COM              438516106   1,393    31,700  SH      SOLE                  31,700
HSN INC                        COM              404303109   4,273   142,900  SH      SOLE                 142,900
HUMANA INC                     COM              444859102   1,713    34,100  SH      SOLE                  34,100
HUNTSMAN CORP                  COM              447011107   4,281   370,300  SH      SOLE                 370,300
IDT CORP                       COM              448947507   1,005    56,500  SH      SOLE                  56,500
INERGY HLDGS L P               COM              45661Q107     650    21,500  SH      SOLE                  21,500
INTEL CORP                     COM              458140100   5,474   284,650  SH      SOLE                 284,650
INTERFACE INC                  COM              458665106     657    46,200  SH      SOLE                  46,200
INTERNATIONAL BUSINESS MACHS   COM              459200101   1,543    11,500  SH      SOLE                  11,500
JO-ANN STORES INC              COM              47758P307   9,315   209,100  SH      SOLE                 209,100
JOE'S JEANS INC                COM              47777N101      37    17,620  SH      SOLE                  17,620
JOHNSON & JOHNSON              COM              478160104   5,381    86,850  SH      SOLE                  86,850
JONES LANG LASALLE INC         COM              48020Q107   4,572    53,000  SH      SOLE                  53,000
JOY GLOBAL INC                 COM              481165108   1,730    24,600  SH      SOLE                  24,600
KAPSTONE PAPER & PACKAGING CRP COM              48562P103   5,693   468,940  SH      SOLE                 468,940
KELLOGG CO                     COM              487836108   1,434    28,400  SH      SOLE                  28,400
KIMBERLY CLARK CORP            COM              494368103   4,612    70,900  SH      SOLE                  70,900
KIRKLANDS INC                  COM              497498105   3,258   235,070  SH      SOLE                 235,070
KNOLOGY INC                    COM              499183804   4,795   357,000  SH      SOLE                 357,000
KRAFT FOODS INC                COM              50075N104   8,400   272,200  SH      SOLE                 272,200
KRISPY KREME DOUGHNUTS INC     COM              501014104      48    10,550  SH      SOLE                  10,550
LA Z BOY INC                   COM              505336107   3,243   384,300  SH      SOLE                 384,300
LABORATORY CORP AMER HLDGS     COM              50540R409   1,506    19,200  SH      SOLE                  19,200
LEXMARK INTL NEW               COM              529771107   4,591   102,900  SH      SOLE                 102,900
LIBBEY INC                     COM              529898108     547    41,500  SH      SOLE                  41,500
LIBERTY GLOBAL INC             COM              530555101   1,670    54,200  SH      SOLE                  54,200
LIFETIME BRANDS INC            COM              53222Q103     533    35,300  SH      SOLE                  35,300
LILLY ELI & CO                 COM              532457108   1,556    42,600  SH      SOLE                  42,600
LIMITED BRANDS INC             COM              532716107   4,167   155,600  SH      SOLE                 155,600
LIONBRIDGE TECHNOLOGIES INC    COM              536252109     479   111,400  SH      SOLE                 111,400
LOCKHEED MARTIN CORP           COM              539830109   3,999    56,100  SH      SOLE                  56,100
LORAL SPACE & COMMUNICATNS INC COM              543881106     699    13,400  SH      SOLE                  13,400
LORILLARD INC                  COM              544147101   1,542    19,200  SH      SOLE                  19,200
LUBRIZOL CORP                  COM              549271104   6,061    57,200  SH      SOLE                  57,200
LUMBER LIQUIDATORS HLDGS INC   COM              55003T107   3,504   142,600  SH      SOLE                 142,600
M & F WORLDWIDE CORP           COM              552541104   2,686   110,300  SH      SOLE                 110,300
MACQUARIE INFRASTR CO LLC      COM              55608B105     622    40,100  SH      SOLE                  40,100
MAGELLAN HEALTH SVCS INC       COM              559079207   4,549    96,300  SH      SOLE                  96,300
MARATHON OIL CORP              COM              565849106   3,151    95,200  SH      SOLE                  95,200
MARSH & MCLENNAN COS INC       COM              571748102   3,271   135,600  SH      SOLE                 135,600
MASSEY ENERGY COMPANY          COM              576206106   2,978    96,000  SH      SOLE                  96,000
MATTEL INC                     COM              577081102   4,964   211,600  SH      SOLE                 211,600
MCDONALDS CORP                 COM              580135101   7,313    98,150  SH      SOLE                  98,150
MCGRAW HILL COS INC            COM              580645109   1,461    44,200  SH      SOLE                  44,200
MEADWESTVACO CORP              COM              583334107   2,606   106,900  SH      SOLE                 106,900
MEDIA GEN INC                  COM              584404107     465    51,900  SH      SOLE                  51,900
MERCK & CO INC NEW             COM              58933Y105   7,841   213,000  SH      SOLE                 213,000
MOBILE TELESYSTEMS OJSC        SPONSORED ADR    607409109   3,235   152,400  SH      SOLE                 152,400
MOODYS CORP                    COM              615369105   1,494    59,800  SH      SOLE                  59,800
NACCO INDS INC                 COM              629579103     507     5,800  SH      SOLE                   5,800
NEENAH PAPER INC               COM              640079109     436    28,700  SH      SOLE                  28,700
NETWORK ENGINES INC            COM              64121A107      32    21,700  SH      SOLE                  21,700
NEWMARKET CORP                 COM              651587107   3,831    33,700  SH      SOLE                  33,700
NOKIA CORP                     SPONSORED ADR    654902204   2,370   236,300  SH      SOLE                 236,300
NU SKIN ENTERPRISES INC        COM              67018T105   3,819   132,600  SH      SOLE                 132,600
NUCOR CORP                     COM              670346105   2,563    67,100  SH      SOLE                  67,100
OMNOVA SOLUTIONS INC           COM              682129101   3,962   550,990  SH      SOLE                 550,990
OWENS CORNING NEW              COM              690742101     446    17,400  SH      SOLE                  17,400
PACER INTL INC TENN            COM              69373H106     471    77,900  SH      SOLE                  77,900
PATRIOT COAL CORP              COM              70336T104   3,269   286,500  SH      SOLE                 286,500
PFIZER INC                     COM              717081103   7,851   457,250  SH      SOLE                 457,250
PHILIP MORRIS INTL INC         COM              718172109   5,109    91,200  SH      SOLE                  91,200
PITNEY BOWES INC               COM              724479100   2,754   128,800  SH      SOLE                 128,800
POLYONE CORP                   COM              73179P106   4,609   381,200  SH      SOLE                 381,200
POWER ONE INC NEW              COM              73930R102     684    75,300  SH      SOLE                  75,300
PPG INDS INC                   COM              693506107   3,706    50,900  SH      SOLE                  50,900
PROVIDENCE SVC CORP            COM              743815102   4,111   250,800  SH      SOLE                 250,800
QUAKER CHEM CORP               COM              747316107     628    19,300  SH      SOLE                  19,300
RAYTHEON CO                    COM              755111507   1,179    25,800  SH      SOLE                  25,800
REGENCY ENERGY PARTNERS L P    COM              75885Y107   4,654   190,100  SH      SOLE                 190,100
REVLON INC                     COM              761525609   2,518   199,500  SH      SOLE                 199,500
REYNOLDS AMERICAN INC          COM              761713106   3,290    55,400  SH      SOLE                  55,400
ROCKWOOD HLDGS INC             COM              774415103   4,349   138,200  SH      SOLE                 138,200
ROSS STORES INC                COM              778296103   1,420    26,000  SH      SOLE                  26,000
ROYAL DUTCH SHELL PLC          SPONS ADR A      780259206   3,057    50,700  SH      SOLE                  50,700
SAIC INC                       COM              78390X101   1,318    82,500  SH      SOLE                  82,500
SANMINA SCI CORP               COM              800907206   5,283   437,300  SH      SOLE                 437,300
SARA LEE CORP                  COM              803111103   3,309   246,400  SH      SOLE                 246,400
SCHWEITZER-MAUDUIT INTL INC    COM              808541106   3,481    59,700  SH      SOLE                  59,700
SELECT COMFORT CORP            COM              81616X103     401    59,100  SH      SOLE                  59,100
SINCLAIR BROADCAST GROUP INC   CL A             829226109     592    84,300  SH      SOLE                  84,300
SKECHERS U S A INC             COM              830566105     329    14,000  SH      SOLE                  14,000
STANDEX INTL CORP              COM              854231107     508    21,000  SH      SOLE                  21,000
SXC HEALTH SOLUTIONS CORP      COM              78505P100   5,500   150,806  SH      SOLE                 150,806
SYSCO CORP                     COM              871829107   4,446   155,900  SH      SOLE                 155,900
TAIWAN SEMICONDUCTOR MFG LTD   SPONSORED ADR    874039100   2,685   264,800  SH      SOLE                 264,800
TECH DATA CORP                 COM              878237106   3,494    86,700  SH      SOLE                  86,700
TELEFONICA S A                 SPONSORED ADR    879382208   2,655    35,800  SH      SOLE                  35,800
TELVENT GIT SA                 SHS              E90215109   2,466   109,000  SH      SOLE                 109,000
TENNANT CO                     COM              880345103     501    16,200  SH      SOLE                  16,200
TENNECO INC                    COM              880349105   4,519   156,000  SH      SOLE                 156,000
TIM PARTICIPACOES S A          SPONS ADR PFD    88706P106   4,299   130,300  SH      SOLE                 130,300
TJX COS INC NEW                COM              872540109   1,410    31,600  SH      SOLE                  31,600
TORO CO                        COM              891092108   4,330    77,000  SH      SOLE                  77,000
TOTAL S A                      SPONSORED ADR    89151E109   2,487    48,200  SH      SOLE                  48,200
TRACTOR SUPPLY CO              COM              892356106   4,519   113,936  SH      SOLE                 113,936
TRIMAS CORP                    COM              896215209     711    47,900  SH      SOLE                  47,900
TRW AUTOMOTIVE HLDGS CORP      COM              87264S106   5,723   137,700  SH      SOLE                 137,700
U S AIRWAYS GROUP INC          COM              90341W108   4,958   536,000  SH      SOLE                 536,000
UAL CORP                       COM              902549807   5,241   221,800  SH      SOLE                 221,800
ULTA SALON COSMETCS & FRAG INC COM              90384S303  11,073   379,200  SH      SOLE                 379,200
ULTRA CLEAN HLDGS INC          COM              90385V107     546    63,300  SH      SOLE                  63,300
UNISYS CORP                    COM              909214306   3,136   112,400  SH      SOLE                 112,400
UNITED PARCEL SERVICE INC      COM              911312106   3,381    50,700  SH      SOLE                  50,700
UNIVERSAL AMERICAN CORP        COM              913377107     527    35,700  SH      SOLE                  35,700
VALASSIS COMMUNICATIONS INC    COM              918866104   4,928   145,400  SH      SOLE                 145,400
VERIZON COMMUNICATIONS INC     COM              92343V104   8,130   249,450  SH      SOLE                 249,450
VIRGIN MEDIA INC               COM              92769L101   5,145   223,500  SH      SOLE                 223,500
VIVO PARTICIPACOES S A         SPON ADR PFD NEW 92855S200   3,114   114,600  SH      SOLE                 114,600
VODAFONE GROUP PLC NEW         SPONS ADR NEW    92857W209   3,263   131,500  SH      SOLE                 131,500
WASTE MGMT INC DEL             COM              94106L109   3,188    89,200  SH      SOLE                  89,200
WESTELL TECH INC               CL A             957541105      54    23,580  SH      SOLE                  23,580
WESTERN DIGITAL CORP           COM              958102105     985    34,700  SH      SOLE                  34,700
WHIRLPOOL CORP                 COM              963320106     470     5,800  SH      SOLE                   5,800
WILLIAMS SONOMA INC            COM              969904101   4,438   140,000  SH      SOLE                 140,000
WYNDHAM WORLDWIDE CORP         COM              98310W108   4,313   157,000  SH      SOLE                 157,000
XL GROUP PLC                   SHS              G98290102   4,321   199,500  SH      SOLE                 199,500
YUM BRANDS INC                 COM              988498101   1,598    34,700  SH      SOLE                  34,700
ZIONS BANCORPORATION           COM              989701107     502    23,500  SH      SOLE                  23,500
TOTAL                                                     651,605