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

                                    Form 13F

                              FORM 13F COVER PAGE

Report for the Calendar Year or Quarter Ended:  March 31, 2011

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                   April 19, 2011
--------------------------------------------------------------------------------
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:         200
                                         -------------
Form 13F Information Table Value Total:    $690,949
                                         -------------
                                          (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
------------------------------ ---------------- --------- -------- -------- --- ---- ------- ------------ -------- -------- -------
                                                                                                 
ABBOTT LABS                    COM              002824100   2,659    54,200  SH      SOLE                  54,200
ADVANCE AUTO PARTS INC         COM              00751Y106   4,830    73,600  SH      SOLE                  73,600
AIR TRANSPORT SERVICES GRP INC COM              00922R105   5,078   601,000  SH      SOLE                 601,000
ALAMO GROUP INC                COM              011311107     728    26,520  SH      SOLE                  26,520
ALASKA AIR GROUP INC           COM              011659109     755    11,900  SH      SOLE                  11,900
ALTRIA GROUP INC               COM              02209S103   4,534   174,200  SH      SOLE                 174,200
AMERCO                         COM              023586100   3,647    37,600  SH      SOLE                  37,600
AMERICAN INTL GROUP INC        COM              026874784     538    15,300  SH      SOLE                  15,300
AMERIGROUP CORP                COM              03073T102   7,170   111,600  SH      SOLE                 111,600
ANN INC                        COM              035623107   4,279   147,000  SH      SOLE                 147,000
APOLLO GROUP INC               COM              037604105     968    23,200  SH      SOLE                  23,200
APPLIED INDL TECHNOLOGIES INC  COM              03820C105   4,813   144,700  SH      SOLE                 144,700
ASHFORD HOSPITALITY TR INC     COM              044103109   4,255   386,100  SH      SOLE                 386,100
AT&T INC                       COM              00206R102   8,020   262,100  SH      SOLE                 262,100
ATLAS ENERGY LP                COM              04930A104   5,945   266,100  SH      SOLE                 266,100
ATLAS PIPELINE PARTNERS LP     COM              049392103   5,461   158,300  SH      SOLE                 158,300
AUTOLIV INC                    COM               52800109   5,233    70,500  SH      SOLE                  70,500
AUTOMATIC DATA PROCESSING INC  COM              053015103   2,950    57,500  SH      SOLE                  57,500
AUTOZONE INC                   COM              053332102   2,161     7,900  SH      SOLE                   7,900
AXCELIS TECHNOLOGIES INC       COM              054540109      34    12,760  SH      SOLE                  12,760
BANCO MACRO SA                 SPON ADR B       05961W105     737    18,400  SH      SOLE                  18,400
BAXTER INTL INC                COM              071813109   1,624    30,200  SH      SOLE                  30,200
BCE INC                        COM NEW          05534B760   2,893    79,600  SH      SOLE                  79,600
BECTON DICKINSON & CO          COM              075887109   1,505    18,900  SH      SOLE                  18,900
BEST BUY INC                   COM              086516101     885    30,800  SH      SOLE                  30,800
BORGWARNER INC                 COM              099724106  11,866   148,900  SH      SOLE                 148,900
BRISTOL MYERS SQUIBB CO        COM              110122108   4,184   158,300  SH      SOLE                 158,300
BROWN SHOE INC NEW             COM              115736100     414    33,900  SH      SOLE                  33,900
BUCKEYE TECHNOLOGIES INC       COM              118255108   5,106   187,500  SH      SOLE                 187,500
CALLON PETE CO DEL             COM              13123X102     718    92,400  SH      SOLE                  92,400
CAMPBELL SOUP CO               COM              134429109   3,844   116,100  SH      SOLE                 116,100
CARDINAL HEALTH INC            COM              14149Y108   1,653    40,200  SH      SOLE                  40,200
CARDTRONICS INC                COM              14161H108     912    44,800  SH      SOLE                  44,800
CASCADE CORP                   COM              147195101     646    14,500  SH      SOLE                  14,500
CENTURYLINK INC                COM              156700106   2,559    61,600  SH      SOLE                  61,600
CHEVRON CORP NEW               COM              166764100   9,303    86,600  SH      SOLE                  86,600
CHINA MOBILE LIMITED           SPONSORED ADR    16941M109   2,354    50,900  SH      SOLE                  50,900
CIGNA CORP                     COM              125509109   1,962    44,300  SH      SOLE                  44,300
CLEARWATER PAPER CORP          COM              18538R103     781     9,600  SH      SOLE                   9,600
CLOROX CO DEL                  COM              189054109   1,577    22,500  SH      SOLE                  22,500
COCA COLA CO                   COM              191216100   1,758    26,500  SH      SOLE                  26,500
COMMERCIAL VEH GROUP INC       COM              202608105   4,869   272,900  SH      SOLE                 272,900
COMPANHIA SIDERURGICA NACIONAL SPONSORED ADR    20440W105   2,557   153,500  SH      SOLE                 153,500
COMPLETE PRODUCTION SERVICES   COM              20453E109   6,400   201,200  SH      SOLE                 201,200
CONAGRA FOODS INC              COM              205887102   2,867   120,700  SH      SOLE                 120,700
CONOCOPHILLIPS                 COM              20825C104   3,354    42,000  SH      SOLE                  42,000
CONSOL ENERGY INC              COM              20854P109   1,775    33,100  SH      SOLE                  33,100
CONSOLIDATED GRAPHICS INC      COM              209341106     666    12,200  SH      SOLE                  12,200
COST PLUS INC CALIF            COM              221485105   3,754   382,300  SH      SOLE                 382,300
CPI CORP                       COM              125902106   3,100   137,700  SH      SOLE                 137,700
CROCS INC                      COM              227046109   7,505   420,700  SH      SOLE                 420,700
CROWN HOLDINGS INC             COM              228368106   2,052    53,200  SH      SOLE                  53,200
DDI CORP                       COM              233162502   3,606   341,140  SH      SOLE                 341,140
DIAGEO P L C                   SPON ADR NEW     25243Q205   2,660    34,900  SH      SOLE                  34,900
DIAMOND OFFSHORE DRILLING INC  COM              25271C102   1,321    17,000  SH      SOLE                  17,000
DILLARDS INC                   COM              254067101   4,341   108,200  SH      SOLE                 108,200
DINEEQUITY INC                 COM              254423106   3,898    70,900  SH      SOLE                  70,900
DIRECTV                        COM              25490A101   1,863    39,800  SH      SOLE                  39,800
DISH NETWORK CORP              COM              25470M109   1,586    65,100  SH      SOLE                  65,100
DOLLAR TREE INC                COM              256746108   6,940   125,000  SH      SOLE                 125,000
DU PONT E I DE NEMOURS & CO    COM              263534109   8,968   163,150  SH      SOLE                 163,150
EMCORE CORP                    COM              290846104      41    15,810  SH      SOLE                  15,810
ENI S P A                      SPONSORED ADR    26874R108   2,894    58,900  SH      SOLE                  58,900
ENTERPRISE PRODS PARTNERS L P  COM              293792107   2,597    60,300  SH      SOLE                  60,300
ESTERLINE TECHNOLOGIES CORP    COM              297425100     785    11,100  SH      SOLE                  11,100
EXPRESS-1 EXPEDITED SOLTNS     COM              30217Q108      29    13,520  SH      SOLE                  13,520
F M C CORP                     COM              302491303   1,911    22,500  SH      SOLE                  22,500
FAMILY DLR STORES INC          COM              307000109   6,959   135,600  SH      SOLE                 135,600
FERRO CORP                     COM              315405100   5,748   346,500  SH      SOLE                 346,500
FLOWSERVE CORP                 COM              34354P105   1,597    12,400  SH      SOLE                  12,400
FLUOR CORP NEW                 COM              343412102   2,018    27,400  SH      SOLE                  27,400
FOREST LABS INC                COM              345838106   1,712    53,000  SH      SOLE                  53,000
FRANCE TELECOM                 SPONSORED ADR    35177Q105   2,566   114,000  SH      SOLE                 114,000
FREEPORT-MCMORAN COPPER & GOLD COM              35671D857   2,089    37,600  SH      SOLE                  37,600
GAP INC DEL                    COM              364760108   1,292    57,000  SH      SOLE                  57,000
GARDNER DENVER INC             COM              365558105     905    11,600  SH      SOLE                  11,600
GENERAL COMMUNICATION INC      COM              369385109   3,455   315,800  SH      SOLE                 315,800
GENERAL MLS INC                COM              370334104   4,170   114,100  SH      SOLE                 114,100
GLAXOSMITHKLINE PLC            SPONSORED ADR    37733W105   2,554    66,500  SH      SOLE                  66,500
GREENBRIER COS INC             COM              393657101   4,881   172,000  SH      SOLE                 172,000
GRUPO FINANCIERO GALICIA S A   SP ADR 10 SH B   399909100   3,163   254,500  SH      SOLE                 254,500
HEALTHSPRING INC               COM              42224N101   6,973   186,600  SH      SOLE                 186,600
HEINZ H J CO                   COM              423074103   4,184    85,700  SH      SOLE                  85,700
HILL ROM HLDGS INC             COM              431475102     691    18,200  SH      SOLE                  18,200
HOME DEPOT INC                 COM              437076102   2,361    63,700  SH      SOLE                  63,700
HONEYWELL INTL INC             COM              438516106   1,821    30,500  SH      SOLE                  30,500
HSN INC                        COM              404303109   4,561   142,400  SH      SOLE                 142,400
HUMANA INC                     COM              444859102   2,301    32,900  SH      SOLE                  32,900
IDT CORP                       COM              448947507   5,244   194,600  SH      SOLE                 194,600
INNOSPEC INC                   COM              45768S105   5,781   181,000  SH      SOLE                 181,000
INTEL CORP                     COM              458140100   6,721   333,200  SH      SOLE                 333,200
INTERFACE INC                  COM              458665106   5,547   300,000  SH      SOLE                 300,000
INTERNATIONAL BUSINESS MACHS   COM              459200101   1,810    11,100  SH      SOLE                  11,100
IPASS INC                      COM              46261V108      35    22,730  SH      SOLE                  22,730
ISTAR FINL INC                 COM              45031U101   5,179   564,200  SH      SOLE                 564,200
JOHNSON & JOHNSON              COM              478160104   8,455   142,700  SH      SOLE                 142,700
JONES LANG LASALLE INC         COM              48020Q107   5,266    52,800  SH      SOLE                  52,800
JOY GLOBAL INC                 COM              481165108   2,342    23,700  SH      SOLE                  23,700
KELLOGG CO                     COM              487836108   4,362    80,800  SH      SOLE                  80,800
KEMET CORP                     COM              488360207   4,538   306,000  SH      SOLE                 306,000
KIMBERLY CLARK CORP            COM              494368103   4,282    65,600  SH      SOLE                  65,600
KRAFT FOODS INC                COM              50075N104   7,577   241,600  SH      SOLE                 241,600
KRISPY KREME DOUGHNUTS INC     COM              501014104   3,828   543,730  SH      SOLE                 543,730
KT CORP                        SPONSORED ADR    48268K101   2,324   119,000  SH      SOLE                 119,000
LABORATORY CORP AMER HLDGS     COM              50540R409   1,704    18,500  SH      SOLE                  18,500
LEXMARK INTL NEW               COM              529771107   3,797   102,500  SH      SOLE                 102,500
LIBBEY INC                     COM              529898108   5,181   314,000  SH      SOLE                 314,000
LIBERTY GLOBAL INC             COM              530555101   2,166    52,300  SH      SOLE                  52,300
LIFETIME BRANDS INC            COM              53222Q103     537    35,800  SH      SOLE                  35,800
LILLY ELI & CO                 COM              532457108   4,094   116,400  SH      SOLE                 116,400
LIONBRIDGE TECHNOLOGIES INC    COM              536252109     387   112,800  SH      SOLE                 112,800
LOCKHEED MARTIN CORP           COM              539830109   4,390    54,600  SH      SOLE                  54,600
LORAL SPACE & COMMUNICATNS INC COM              543881106   1,055    13,600  SH      SOLE                  13,600
LORILLARD INC                  COM              544147101   1,758    18,500  SH      SOLE                  18,500
LUBRIZOL CORP                  COM              549271104   7,569    56,500  SH      SOLE                  56,500
MACQUARIE INFRASTR CO LLC      COM              55608B105     969    40,600  SH      SOLE                  40,600
MAGELLAN HEALTH SVCS INC       COM              559079207   4,707    95,900  SH      SOLE                  95,900
MAGNETEK INC                   COM              559424106      37    16,760  SH      SOLE                  16,760
MARSH & MCLENNAN COS INC       COM              571748102   3,056   102,500  SH      SOLE                 102,500
MATERION CORP                  COM              576690101   4,182   102,500  SH      SOLE                 102,500
MATTEL INC                     COM              577081102   4,298   172,400  SH      SOLE                 172,400
MCDONALDS CORP                 COM              580135101   3,321    43,650  SH      SOLE                  43,650
MCGRAW HILL COS INC            COM              580645109   1,678    42,600  SH      SOLE                  42,600
MEDCATH CORP                   COM              58404W109   4,075   292,140  SH      SOLE                 292,140
MEDIA GEN INC                  COM              584404107     361    52,500  SH      SOLE                  52,500
MERCER INTL INC                COM              588056101   7,858   579,900  SH      SOLE                 579,900
MERCK & CO INC NEW             COM              58933Y105   7,350   222,650  SH      SOLE                 222,650
MERITOR INC                    COM              59001K100   5,692   335,400  SH      SOLE                 335,400
MOBILE TELESYSTEMS OJSC        SPONSORED ADR    607409109   2,588   121,900  SH      SOLE                 121,900
MOODYS CORP                    COM              615369105   1,957    57,700  SH      SOLE                  57,700
MRV COMMUNICATIONS INC         COM              553477100      30    19,870  SH      SOLE                  19,870
NACCO INDS INC                 COM              629579103   4,715    42,600  SH      SOLE                  42,600
NEENAH PAPER INC               COM              640079109     639    29,100  SH      SOLE                  29,100
NEWCASTLE INVT CORP            COM              65105M108   4,018   665,200  SH      SOLE                 665,200
NEWPORT CORP                   COM              651824104   4,108   230,400  SH      SOLE                 230,400
NOKIA CORP                     SPONSORED ADR    654902204   2,154   253,100  SH      SOLE                 253,100
OPNEXT INC                     COM              68375V105      27    11,020  SH      SOLE                  11,020
OWENS CORNING NEW              COM              690742101     633    17,600  SH      SOLE                  17,600
PACER INTL INC TENN            COM              69373H106     415    78,900  SH      SOLE                  78,900
PETROCHINA CO LTD              SPONSORED ADR    71646E100   3,075    20,200  SH      SOLE                  20,200
PFIZER INC                     COM              717081103   9,089   447,500  SH      SOLE                 447,500
PHILIP MORRIS INTL INC         COM              718172109   4,824    73,500  SH      SOLE                  73,500
PIER 1 IMPORTS INC             COM              720279108   3,792   373,600  SH      SOLE                 373,600
PITNEY BOWES INC               COM              724479100   2,872   111,800  SH      SOLE                 111,800
POLYONE CORP                   COM              73179P106   5,430   382,100  SH      SOLE                 382,100
POWER ONE INC NEW              COM              73930R102   3,760   429,700  SH      SOLE                 429,700
POWERWAVE TECHNOLOGIES INC     COM              739363109      46    10,240  SH      SOLE                  10,240
PRICESMART INC                 COM              741511109   3,734   101,900  SH      SOLE                 101,900
PROCTER & GAMBLE CO            COM              742718109     810    13,150  SH      SOLE                  13,150
QUAKER CHEM CORP               COM              747316107   4,647   115,690  SH      SOLE                 115,690
QUIKSILVER INC                 COM              74838C106   3,426   775,200  SH      SOLE                 775,200
RAYTHEON CO                    COM              755111507   4,120    81,000  SH      SOLE                  81,000
ROCHE HLDG LTD                 ADR              771195104   2,588    72,000  SH      SOLE                  72,000
ROCKWOOD HLDGS INC             COM              774415103   6,778   137,700  SH      SOLE                 137,700
ROSS STORES INC                COM              778296103   1,785    25,100  SH      SOLE                  25,100
ROYAL DUTCH SHELL PLC          SPON ADR A       780259206   2,907    39,900  SH      SOLE                  39,900
RUBY TUESDAY INC               COM              781182100   3,777   288,100  SH      SOLE                 288,100
SAIC INC                       COM              78390X101   1,347    79,600  SH      SOLE                  79,600
SANOFI AVENTIS                 SPONSORED ADR    80105N105   2,737    77,700  SH      SOLE                  77,700
SAUER-DANFOSS INC              COM              804137107   6,376   125,200  SH      SOLE                 125,200
SELECT COMFORT CORP            COM              81616X103     721    59,800  SH      SOLE                  59,800
SINCLAIR BROADCAST GROUP INC   CL A             829226109   1,070    85,300  SH      SOLE                  85,300
SKECHERS U S A INC             COM              830566105     292    14,200  SH      SOLE                  14,200
STANDEX INTL CORP              COM              854231107     807    21,300  SH      SOLE                  21,300
STATOIL ASA                    SPONSORED ADR    85771P102   3,394   122,800  SH      SOLE                 122,800
SUNOPTA INC                    COM              8676EP108   3,885   523,600  SH      SOLE                 523,600
SXC HEALTH SOLUTIONS CORP      COM              78505P100     844    15,400  SH      SOLE                  15,400
SYSCO CORP                     COM              871829107   3,795   137,000  SH      SOLE                 137,000
TAIWAN SEMICONDUCTOR MFG LTD   SPONSORED ADR    874039100   2,873   235,900  SH      SOLE                 235,900
TELEFONICA S A                 SPONSORED ADR    879382208   2,676   106,100  SH      SOLE                 106,100
TENNANT CO                     COM              880345103     689    16,400  SH      SOLE                  16,400
TENNECO INC                    COM              880349105  10,642   250,700  SH      SOLE                 250,700
TIMKEN CO                      COM              887389104   4,310    82,400  SH      SOLE                  82,400
TITAN INTL INC ILL             COM              88830M102   5,649   212,300  SH      SOLE                 212,300
TJX COS INC NEW                COM              872540109   1,517    30,500  SH      SOLE                  30,500
TORO CO                        COM              891092108   5,079    76,700  SH      SOLE                  76,700
TOTAL S A                      SPONSORED ADR    89151E109   2,963    48,600  SH      SOLE                  48,600
TPC GROUP INC                  COM              89236Y104   4,059   140,600  SH      SOLE                 140,600
TRACTOR SUPPLY CO              COM              892356106  11,685   195,200  SH      SOLE                 195,200
TRIMAS CORP                    COM              896215209   4,814   223,900  SH      SOLE                 223,900
TRW AUTOMOTIVE HLDGS CORP      COM              87264S106  11,749   213,300  SH      SOLE                 213,300
TUESDAY MORNING CORP           COM              899035505   3,496   713,400  SH      SOLE                 713,400
U S AIRWAYS GROUP INC          COM              90341W108   7,797   895,200  SH      SOLE                 895,200
ULTA SALON COSMETCS & FRAG INC COM              90384S303   8,524   177,100  SH      SOLE                 177,100
ULTRA CLEAN HLDGS INC          COM              90385V107     691    66,780  SH      SOLE                  66,780
UNITED CONTL HLDGS INC         COM              910047109   8,559   372,300  SH      SOLE                 372,300
UNITED RENTALS INC             COM              911363109   5,574   167,500  SH      SOLE                 167,500
UNIVERSAL AMERICAN CORP        COM              913377107     827    36,100  SH      SOLE                  36,100
VALASSIS COMMUNICATIONS INC    COM              918866104   4,225   145,000  SH      SOLE                 145,000
VERIZON COMMUNICATIONS INC     COM              92343V104   8,899   230,900  SH      SOLE                 230,900
VODAFONE GROUP PLC NEW         SPONS ADR NEW    92857W209   2,691    93,600  SH      SOLE                  93,600
WASTE MGMT INC DEL             COM              94106L109   2,786    74,600  SH      SOLE                  74,600
WESTELL TECH INC               CL A             957541105      38    10,890  SH      SOLE                  10,890
WESTERN DIGITAL CORP           COM              958102105   1,249    33,500  SH      SOLE                  33,500
WESTERN REFNG INC              COM              959319104   6,285   370,800  SH      SOLE                 370,800
WHIRLPOOL CORP                 COM              963320106     504     5,900  SH      SOLE                   5,900
WILLIAMS SONOMA INC            COM              969904101   5,650   139,500  SH      SOLE                 139,500
WYNDHAM WORLDWIDE CORP         COM              98310W108   4,975   156,400  SH      SOLE                 156,400
YUM BRANDS INC                 COM              988498101   1,721    33,500  SH      SOLE                  33,500
ZIONS BANCORPORATION           COM              989701107     549    23,800  SH      SOLE                  23,800
TOTAL                                                     690,949