<SEC-DOCUMENT>0001972362-24-000101.txt : 20240209
<SEC-HEADER>0001972362-24-000101.hdr.sgml : 20240209
<ACCEPTANCE-DATETIME>20240209165601
ACCESSION NUMBER:		0001972362-24-000101
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20240209
DATE AS OF CHANGE:		20240209

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TETRA TECH INC
		CENTRAL INDEX KEY:			0000831641
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ENGINEERING SERVICES [8711]
		ORGANIZATION NAME:           	07 Trade & Services
		IRS NUMBER:				954148514
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0929

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	000-19655
		FILM NUMBER:		24615843

	BUSINESS ADDRESS:	
		STREET 1:		3475 EAST FOOTHILL BOULEVARD
		CITY:			PASADENA
		STATE:			CA
		ZIP:			91107
		BUSINESS PHONE:		6263514664

	MAIL ADDRESS:	
		STREET 1:		3475 EAST FOOTHILL BOULEVARD
		CITY:			PASADENA
		STATE:			CA
		ZIP:			91107

REPORTING-OWNER:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CARTER BRIAN N
		CENTRAL INDEX KEY:			0001561742
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		144

	MAIL ADDRESS:	
		STREET 1:		3475 EAST FOOTHILL BOULEVARD
		CITY:			PASADENA
		STATE:			CA
		ZIP:			91107
</SEC-HEADER>
<DOCUMENT>
<TYPE>144
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?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>0001561742</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0000831641</issuerCik>
      <issuerName>TETRA TECH INC</issuerName>
      <secFileNumber>000-19655</secFileNumber>
      <issuerAddress>
        <com:street1>3475 EAST FOOTHILL BOULEVARD</com:street1>
        <com:city>PASADENA</com:city>
        <com:stateOrCountry>CA</com:stateOrCountry>
        <com:zipCode>91107</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>6263514664</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>CARTER BRIAN N</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Officer</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>MORGAN STANLEY SMITH BARNEY LLC EXECUTIVE SERVICES</name>
        <address>
          <com:street1>200 W CIVIC CENTER DR. 4TH FLOOR</com:street1>
          <com:city>SANDY</com:city>
          <com:stateOrCountry>UT</com:stateOrCountry>
          <com:zipCode>84070</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>5580</noOfUnitsSold>
      <aggregateMarketValue>984981.04</aggregateMarketValue>
      <noOfUnitsOutstanding>53200000</noOfUnitsOutstanding>
      <approxSaleDate>02/09/2024</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <acquiredDate>02/09/2024</acquiredDate>
      <natureOfAcquisitionTransaction>STOCK OPTION EXERCISE</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>ISSUER</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>5580</amountOfSecuritiesAcquired>
      <paymentDate>02/09/2024</paymentDate>
      <natureOfPayment>COMPENSATION</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>BRIAN CARTER</name>
        <address>
          <com:street1>3475 EAST FOOTHILL BOULEVARD</com:street1>
          <com:city>PASADENA</com:city>
          <com:stateOrCountry>CA</com:stateOrCountry>
          <com:zipCode>91107</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>PERFORMANCE SHARES</securitiesClassTitle>
      <saleDate>12/04/2023</saleDate>
      <amountOfSecuritiesSold>1474</amountOfSecuritiesSold>
      <grossProceeds>244064.92</grossProceeds>
    </securitiesSoldInPast3Months>
    <noticeSignature>
      <noticeDate>02/09/2024</noticeDate>
      <signature>/s/ Brian Neal Carter</signature>
    </noticeSignature>
  </formData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
