<SEC-DOCUMENT>0001104659-21-004238-index.html : 20210114
<SEC-HEADER>0001104659-21-004238.hdr.sgml : 20210114
<ACCEPTANCE-DATETIME>20210114160810
ACCESSION NUMBER:		0001104659-21-004238
CONFORMED SUBMISSION TYPE:	DEFA14A
PUBLIC DOCUMENT COUNT:		5
FILED AS OF DATE:		20210114
DATE AS OF CHANGE:		20210114

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:			0927

	FILING VALUES:
		FORM TYPE:		DEFA14A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19655
		FILM NUMBER:		21528807

	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>
<DOCUMENT>
<TYPE>DEFA14A
<SEQUENCE>1
<FILENAME>a21-1483_3defa14a.htm
<DESCRIPTION>DEFA14A
<TEXT>
Document 1 - file: a21-1483_3defa14a.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>g14833cai001.gif
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: g14833cai001.gif

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>3
<FILENAME>g14833cai002.gif
<DESCRIPTION>GRAPHIC
<TEXT>
Document 3 - file: g14833cai002.gif

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>4
<FILENAME>g14833cai003.gif
<DESCRIPTION>GRAPHIC
<TEXT>
Document 4 - file: g14833cai003.gif

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>5
<FILENAME>g14833cai004.gif
<DESCRIPTION>GRAPHIC
<TEXT>
Document 5 - file: g14833cai004.gif

</DOCUMENT>
</SEC-DOCUMENT>