<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>144</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001165097</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0001145255</issuerCik>
      <issuerName>HENNESSY ADVISORS INC</issuerName>
      <secFileNumber>001-36423</secFileNumber>
      <issuerAddress>
        <com:street1>7250 REDWOOD BLVD.</com:street1>
        <com:street2>SUITE 200</com:street2>
        <com:city>NOVATO</com:city>
        <com:stateOrCountry>CA</com:stateOrCountry>
        <com:zipCode>94945</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>415-899-1555</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>SEAVEY THOMAS L</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Director</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>Wells Fargo Clearing Services</name>
        <address>
          <com:street1>1 N. Jefferson Ave.</com:street1>
          <com:city>St. Louis</com:city>
          <com:stateOrCountry>MO</com:stateOrCountry>
          <com:zipCode>63103</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>1657</noOfUnitsSold>
      <aggregateMarketValue>19653.64</aggregateMarketValue>
      <noOfUnitsOutstanding>7780319</noOfUnitsOutstanding>
      <approxSaleDate>12/18/2024</approxSaleDate>
      <securitiesExchangeName>Nasdaq</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>08/06/2003</acquiredDate>
      <natureOfAcquisitionTransaction>RSU/Options/Grants</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>1657</amountOfSecuritiesAcquired>
      <paymentDate>08/06/2023</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Thomas L Seavey</name>
        <address>
          <com:street1>7250 Redwood Blvd.</com:street1>
          <com:street2>Suite 200</com:street2>
          <com:city>Novato</com:city>
          <com:stateOrCountry>CA</com:stateOrCountry>
          <com:zipCode>94945</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common Shares of HNNA</securitiesClassTitle>
      <saleDate>12/07/2024</saleDate>
      <amountOfSecuritiesSold>7269</amountOfSecuritiesSold>
      <grossProceeds>87899.89</grossProceeds>
    </securitiesSoldInPast3Months>
    <remarks>Shares sold today were vs. RSU's, Options, and Grants acquired from 8/6/2023 - 09/18/2024.</remarks>
    <noticeSignature>
      <noticeDate>12/18/2024</noticeDate>
      <signature>Thomas L. Seavey</signature>
    </noticeSignature>
  </formData>
</edgarSubmission>
[{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 3504}]
144
0001165097
XXXXXXXX
LIVE
0001145255
HENNESSY ADVISORS INC
001-36423
7250 REDWOOD BLVD.
SUITE 200
NOVATO
CA
94945
415-899-1555
SEAVEY THOMAS L
Director
Common
Wells Fargo Clearing Services
1 N. Jefferson Ave.
St. Louis
MO
63103
1657
19653.64
7780319
12/18/2024
Nasdaq
Common
08/06/2003
RSU/Options/Grants
Issuer
N
1657
08/06/2023
N/A
N
Thomas L Seavey
7250 Redwood Blvd.
Suite 200
Novato
CA
94945
Common Shares of HNNA
12/07/2024
7269
87899.89
Shares sold today were vs. RSU's, Options, and Grants acquired from 8/6/2023 - 09/18/2024.
12/18/2024
Thomas L. Seavey