content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <headerData>
  <submissionType>144</submissionType>
  <filerInfo>
  <filer>
  <filerCredentials>
  <cik>0001802468</cik>
  <ccc>XXXXXXXX</ccc>
  </filerCredentials>
  </filer>
  <liveTestFlag>LIVE</liveTestFlag>
  </filerInfo>
  </headerData>
  <formData>
  <issuerInfo>
  <issuerCik>0001701732</issuerCik>
  <issuerName>Altair Engineering Inc.	</issuerName>
  <secFileNumber>001-38263</secFileNumber>
  <issuerAddress>
  <street1 xmlns="http://www.sec.gov/edgar/common">1820 E. BIG BEAVER ROAD</street1>
  <city xmlns="http://www.sec.gov/edgar/common">Troy</city>
  <stateOrCountry xmlns="http://www.sec.gov/edgar/common">MI</stateOrCountry>
  <zipCode xmlns="http://www.sec.gov/edgar/common">48083</zipCode>
  </issuerAddress>
  <issuerContactPhone>248-614-2400</issuerContactPhone>
  <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Maitra Raoul</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
  <relationshipsToIssuer>
  <relationshipToIssuer>Officer</relationshipToIssuer>
  </relationshipsToIssuer>
  </issuerInfo>
  <securitiesInformation>
  <securitiesClassTitle>Class A Common Stock</securitiesClassTitle>
  <brokerOrMarketmakerDetails>
  <name>Morgan Stanley Smith Barney LLC</name>
  <address>
  <street1 xmlns="http://www.sec.gov/edgar/common">Harborside 2</street1>
  <street2 xmlns="http://www.sec.gov/edgar/common">200 Hudson Street, Suite 501</street2>
  <city xmlns="http://www.sec.gov/edgar/common">Jersey City</city>
  <stateOrCountry xmlns="http://www.sec.gov/edgar/common">NJ</stateOrCountry>
  <zipCode xmlns="http://www.sec.gov/edgar/common">07311</zipCode>
  </address>
  </brokerOrMarketmakerDetails>
  <noOfUnitsSold>153</noOfUnitsSold>
  <aggregateMarketValue>12910.02</aggregateMarketValue>
  <noOfUnitsOutstanding>56948286</noOfUnitsOutstanding>
  <approxSaleDate>05/08/2024</approxSaleDate>
  <securitiesExchangeName>NASDAQ</securitiesExchangeName>
  </securitiesInformation>
  <securitiesToBeSold>
  <securitiesClassTitle>Class A Common Stock</securitiesClassTitle>
  <acquiredDate>05/07/2024</acquiredDate>
  <natureOfAcquisitionTransaction>Class A Common Stock Restricted Stock Unit Vesting</natureOfAcquisitionTransaction>
  <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
  <isGiftTransaction>N</isGiftTransaction>
  <amountOfSecuritiesAcquired>523</amountOfSecuritiesAcquired>
  <paymentDate>05/07/2024</paymentDate>
  <natureOfPayment>N/A</natureOfPayment>
  </securitiesToBeSold>
  <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
  <securitiesSoldInPast3Months>
  <sellerDetails>
  <name>Raoul Maitra</name>
  <address>
  <street1 xmlns="http://www.sec.gov/edgar/common">1820 E. Big Beaver Rd.</street1>
  <city xmlns="http://www.sec.gov/edgar/common">Troy</city>
  <stateOrCountry xmlns="http://www.sec.gov/edgar/common">MI</stateOrCountry>
  <zipCode xmlns="http://www.sec.gov/edgar/common">48083</zipCode>
  </address>
  </sellerDetails>
  <securitiesClassTitle>Class A Common Stock</securitiesClassTitle>
  <saleDate>02/28/2024</saleDate>
  <amountOfSecuritiesSold>189</amountOfSecuritiesSold>
  <grossProceeds>15810.09</grossProceeds>
  </securitiesSoldInPast3Months>
  <securitiesSoldInPast3Months>
  <sellerDetails>
  <name>Raoul Maitra</name>
  <address>
  <street1 xmlns="http://www.sec.gov/edgar/common">1820 E. Big Beaver Rd.</street1>
  <city xmlns="http://www.sec.gov/edgar/common">Troy</city>
  <stateOrCountry xmlns="http://www.sec.gov/edgar/common">MI</stateOrCountry>
  <zipCode xmlns="http://www.sec.gov/edgar/common">48083</zipCode>
  </address>
  </sellerDetails>
  <securitiesClassTitle>Class A Common Stock</securitiesClassTitle>
  <saleDate>03/04/2024</saleDate>
  <amountOfSecuritiesSold>285</amountOfSecuritiesSold>
  <grossProceeds>24316.20</grossProceeds>
  </securitiesSoldInPast3Months>
  <securitiesSoldInPast3Months>
  <sellerDetails>
  <name>Raoul Maitra</name>
  <address>
  <street1 xmlns="http://www.sec.gov/edgar/common">1820 E. Big Beaver Rd.</street1>
  <city xmlns="http://www.sec.gov/edgar/common">Troy</city>
  <stateOrCountry xmlns="http://www.sec.gov/edgar/common">MI</stateOrCountry>
  <zipCode xmlns="http://www.sec.gov/edgar/common">48083</zipCode>
  </address>
  </sellerDetails>
  <securitiesClassTitle>Class A Common Stock</securitiesClassTitle>
  <saleDate>03/13/2024</saleDate>
  <amountOfSecuritiesSold>75</amountOfSecuritiesSold>
  <grossProceeds>6124.50</grossProceeds>
  </securitiesSoldInPast3Months>
  <remarks>Represents registered Class A common stock sold pursuant to the Issuer's 2017 Equity Incentive Plan for sell-to-cover transactions for tax withholding obligations resulting from the vesting of Class A common stock restricted stock units. Such sale was previously reported on a Form 4.</remarks>
  <noticeSignature>
  <noticeDate>05/20/2024</noticeDate>
  <signature>Raoul Maitra</signature>
  </noticeSignature>
  </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 4917}]
text: 144
  0001802468
  XXXXXXXX
  LIVE
  0001701732
  Altair Engineering Inc.
  001-38263
  1820 E. BIG BEAVER ROAD
  Troy
  MI
  48083
  248-614-2400
  Maitra Raoul
  Officer
  Class A Common Stock
  Morgan Stanley Smith Barney LLC
  Harborside 2
  200 Hudson Street, Suite 501
  Jersey City
  NJ
  07311
  153
  12910.02
  56948286
  05/08/2024
  NASDAQ
  Class A Common Stock
  05/07/2024
  Class A Common Stock Restricted Stock Unit Vesting
  Issuer
  N
  523
  05/07/2024
  N/A
  N
  Raoul Maitra
  1820 E. Big Beaver Rd.
  Troy
  MI
  48083
  Class A Common Stock
  02/28/2024
  189
  15810.09
  Raoul Maitra
  1820 E. Big Beaver Rd.
  Troy
  MI
  48083
  Class A Common Stock
  03/04/2024
  285
  24316.20
  Raoul Maitra
  1820 E. Big Beaver Rd.
  Troy
  MI
  48083
  Class A Common Stock
  03/13/2024
  75
  6124.50
  Represents registered Class A common stock sold pursuant to the Issuer's 2017 Equity Incentive Plan for sell-to-cover transactions for tax withholding obligations resulting from the vesting of Class A common stock restricted stock units. Such sale was previously reported on a Form 4.
  05/20/2024
  Raoul Maitra