    <SEC-DOCUMENT>0001104659-23-004232-index.html : 20230117
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    <ACCEPTANCE-DATETIME>20230117160052
    ACCESSION NUMBER:		0001104659-23-004232
    CONFORMED SUBMISSION TYPE:	DEF 14A
    PUBLIC DOCUMENT COUNT:		39
    CONFORMED PERIOD OF REPORT:	20230228
    FILED AS OF DATE:		20230117
    DATE AS OF CHANGE:		20230117

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			TETRA TECH INC
    		CENTRAL INDEX KEY:			0000831641
    		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ENGINEERING SERVICES [8711]
    		IRS NUMBER:				954148514
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1002

    	FILING VALUES:
    		FORM TYPE:		DEF 14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-19655
    		FILM NUMBER:		23531549

    	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
    </SEC-HEADER>
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    <TYPE>DEF 14A
    <SEQUENCE>1
    <FILENAME>tm233327-1_def14a.htm
    <DESCRIPTION>DEF 14A
    <TEXT>
    Document 1 - file: tm233327-1_def14a.htm

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>bc_1yrtsr-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: bc_1yrtsr-pn.jpg

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    <SEQUENCE>3
    <FILENAME>bc_3yrtsr-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: bc_3yrtsr-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>bc_nominee-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: bc_nominee-pn.jpg

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    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>bc_targettdc-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: bc_targettdc-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
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    <FILENAME>cv_obc-4c.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: cv_obc-4c.jpg

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    <SEQUENCE>7
    <FILENAME>cv_ofc-4c.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: cv_ofc-4c.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>fc_aip-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: fc_aip-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>fc_aipaward-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: fc_aipaward-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>fc_areas-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: fc_areas-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>ic_donot-pn.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: ic_donot-pn.gif

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>ic_tick-pn.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: ic_tick-pn.gif

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>lg_tetratech-4c.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: lg_tetratech-4c.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>pc_annual-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: pc_annual-pn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>pc_ceoneo-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 15 - file: pc_ceoneo-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>pc_directordiversity-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 16 - file: pc_directordiversity-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>pc_directornominees-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: pc_directornominees-pn.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>ph_christianaobiaya-bwlr.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 18 - file: ph_christianaobiaya-bwlr.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>ph_danbatrack-bw.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 19 - file: ph_danbatrack-bw.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>ph_danbatrack-bwlr.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 20 - file: ph_danbatrack-bwlr.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>21
    <FILENAME>ph_garyrbirken-bwlr.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 21 - file: ph_garyrbirken-bwlr.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>22
    <FILENAME>ph_kenneththom-bwlr.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 22 - file: ph_kenneththom-bwlr.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>23
    <FILENAME>ph_kimberlyrit-bwlr.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 23 - file: ph_kimberlyrit-bwlr.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>24
    <FILENAME>ph_kirstenvolp-bwlr.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 24 - file: ph_kirstenvolp-bwlr.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>25
    <FILENAME>ph_maguirejoanne22-bw.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 25 - file: ph_maguirejoanne22-bw.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>26
    <FILENAME>ph_prashantgandhi-bwlr.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 26 - file: ph_prashantgandhi-bwlr.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>27
    <FILENAME>px_annual-bw.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 27 - file: px_annual-bw.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>28
    <FILENAME>px_scanto-bw.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 28 - file: px_scanto-bw.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>29
    <FILENAME>sg_danbatrack-bw.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 29 - file: sg_danbatrack-bw.jpg

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>30
    <FILENAME>sg_prestonhopson-bw.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 30 - file: sg_prestonhopson-bw.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>31
    <FILENAME>tbl_awardbusiness-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 31 - file: tbl_awardbusiness-pn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>32
    <FILENAME>tbl_ceoneo-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 32 - file: tbl_ceoneo-pn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>33
    <FILENAME>tbl_outreach-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 33 - file: tbl_outreach-pn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>34
    <FILENAME>tbl_tenure-pn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 34 - file: tbl_tenure-pn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>35
    <FILENAME>tm2025328d89-icon_interpn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 35 - file: tm2025328d89-icon_interpn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>36
    <FILENAME>tm2025328d89-icon_mailpn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 36 - file: tm2025328d89-icon_mailpn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>37
    <FILENAME>tm2025328d89-icon_personpn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 37 - file: tm2025328d89-icon_personpn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>38
    <FILENAME>tm2025328d89-icon_telepn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 38 - file: tm2025328d89-icon_telepn.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>39
    <FILENAME>tm2025328d89-icon_waterpn.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 39 - file: tm2025328d89-icon_waterpn.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>