<SEC-DOCUMENT>0001104659-18-005486-index.html : 20180131
<SEC-HEADER>0001104659-18-005486.hdr.sgml : 20180131
<ACCEPTANCE-DATETIME>20180131162705
ACCESSION NUMBER:		0001104659-18-005486
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		3
CONFORMED PERIOD OF REPORT:	20180131
ITEM INFORMATION:		Results of Operations and Financial Condition
ITEM INFORMATION:		Other Events
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20180131
DATE AS OF CHANGE:		20180131

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:			0928

	FILING VALUES:
		FORM TYPE:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19655
		FILM NUMBER:		18563071

	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>8-K
<SEQUENCE>1
<FILENAME>a18-3920_18k.htm
<DESCRIPTION>8-K
<TEXT>
Document 1 - file: a18-3920_18k.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>2
<FILENAME>a18-3920_1ex99d1.htm
<DESCRIPTION>EX-99.1
<TEXT>
Document 2 - file: a18-3920_1ex99d1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>3
<FILENAME>g39201mm01i001.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 3 - file: g39201mm01i001.jpg

</DOCUMENT>
</SEC-DOCUMENT>