| THOMAS COMMUNICATIONS & TECHNOLOGIES, L.L.C.Location not reported, CT · Cancelled | Location not reported, CT | LLC | Jun 10, 2002 | Cancelled |
| TETRA TECH EC, INC.Location not reported, CT · Active | Location not reported, CT | Corporation | Feb 18, 2003 | Active |
| STOCKSHIELD, LLCLocation not reported, CT · Active | Location not reported, CT | Corporation | Jun 3, 2003 | Active |
| SPARKLETTS WATERS OF NORTH AMERICA LIMITED PARTNERSHIPLocation not reported, CT · Cancelled | Location not reported, CT | Partnership | Nov 10, 2003 | Cancelled |
| TETRA TECH FACILITIES CONSTRUCTION, LLCLocation not reported, CT · Withdrawn | Location not reported, CT | LLC | Aug 2, 2007 | Withdrawn |
| TETRA TECH TESORO, INC.Location not reported, CT · Withdrawn | Location not reported, CT | Corporation | Dec 28, 2011 | Withdrawn |
| TETRA TECH ARCHITECTURE, P.C.Location not reported, CT · Active | Location not reported, CT | Corporation | Dec 30, 2011 | Active |
| ROCK GARDEN PRODUCTIONS, INC.Location not reported, CT · Dissolved | Location not reported, CT | Corporation | Oct 10, 2013 | Dissolved |
| BOLTON RGV INC.Location not reported, CT · Withdrawn | Location not reported, CT | Corporation | Oct 18, 2013 | Withdrawn |
| THE WERC SHOP CT, LLCLocation not reported, CT · Dissolved | Location not reported, CT | LLC | Jan 7, 2014 | Dissolved |
| SIM INFOTECH, INC.Location not reported, CT · Withdrawn | Location not reported, CT | Corporation | Sep 3, 2015 | Withdrawn |
| SKYWALKER VOLLEYBALL, LLCLocation not reported, CT · Dissolved | Location not reported, CT | LLC | Apr 15, 2016 | Dissolved |
| TETRA TECH EXECUTIVE SERVICES, INC.Location not reported, CT · Active | Location not reported, CT | Corporation | Dec 10, 2018 | Active |
| NEXTGATE SOLUTIONS, INC.Location not reported, CT · Withdrawn | Location not reported, CT | Corporation | Dec 24, 2018 | Withdrawn |
| SABAL TL1, LLCLocation not reported, CT · Withdrawn | Location not reported, CT | LLC | Apr 22, 2019 | Withdrawn |
| CT CRESCENT PROPERTIES, LLCLocation not reported, CT · Active | Location not reported, CT | LLC | Jul 16, 2019 | Active |
| The Knight's Heart, Inc.Location not reported, CT · Withdrawn | Location not reported, CT | Corporation | Aug 31, 2021 | Withdrawn |
| BYD Auto LLCLocation not reported, CT · Active | Location not reported, CT | LLC | Sep 28, 2022 | Active |
| JADE ROSE PRODUCTIONS, INC.Location not reported, CT · Revoked | Location not reported, CT | Corporation | Mar 7, 2023 | Revoked |
| RSV PRODUCTIONS, INC.Location not reported, CT · Revoked | Location not reported, CT | Corporation | Mar 14, 2023 | Revoked |
| Tetra Tech Engineering and Geology, P.C.Location not reported, CT · Active | Location not reported, CT | Corporation | Oct 8, 2024 | Active |
| Xencor, Inc.Location not reported, CT · Active | Location not reported, CT | Corporation | Jun 17, 2025 | Active |
| Red 8 Studios Corp.Location not reported, CT · Active | Location not reported, CT | Corporation | Feb 10, 2026 | Active |
| TETRA TECH, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Apr 20, 1988 | Active |
| TETRA TECH EC, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Feb 18, 2003 | Active |
| SUPERNATURAL HUMAN LLCLocation not reported, OR · Active | Location not reported, OR | LLC | Dec 5, 2018 | Active |
| TETRA TECH EXECUTIVE SERVICES, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Nov 12, 2020 | Active |
| ADVANCED MANAGEMENT TECHNOLOGY, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Aug 13, 2004 | Active |
| JUMPTOWN LLC, A LIMITED LIABILITY COMPANY OF CALIFORNIALocation not reported, OR · Active | Location not reported, OR | LLC | Oct 24, 2025 | Active |
| BLKXCNCTLocation not reported, OR · Active | Location not reported, OR | Nonprofit | Oct 28, 2025 | Active |
| YES LOGISTICS CORPORATIONLocation not reported, OR · Active | Location not reported, OR | Corporation | Dec 14, 2004 | Active |
| BYD AMERICA LLCLocation not reported, OR · Active | Location not reported, OR | LLC | Mar 17, 2026 | Active |
| JACK BOYAJIAN INSURANCE AGENCY, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Oct 5, 2026 | Active |
| TETRA TECH ARCHITECTURE, P.C.Location not reported, OR · Active | Location not reported, OR | Corporation | Jul 10, 2006 | Active |
| TETRA TECH TECHNICAL SERVICES, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Apr 16, 1999 | Active |
| TETRA TECH BAS, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Jun 28, 2011 | Active |
| LEON MAX, INC.Location not reported, OR · Active | Location not reported, OR | Corporation | Nov 20, 2012 | Active |
| TETRA TECH AMTLocation not reported, OR · Active | Location not reported, OR | Other | Dec 14, 2012 | Active |
| SEA LOG CORPORATIONLocation not reported, FL · Inactive | Location not reported, FL | Corporation | Feb 2, 1967 | Inactive |
| SPARKLETTS WATERS OF NORTH AMERICA, LPLocation not reported, FL · Inactive | Location not reported, FL | Partnership | Nov 7, 2003 | Inactive |
| TWO PLY, L.P.Location not reported, FL · Inactive | Location not reported, FL | Partnership | Oct 22, 2004 | Inactive |
| LC OF ILLINOIS, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Jan 11, 2000 | Inactive |
| TETRA TECH/KCM, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Apr 4, 2000 | Inactive |
| TETRA TECH MM, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Jun 2, 2000 | Inactive |
| MAXIM TECHNOLOGIES OF TEXAS, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Jul 21, 2000 | Inactive |
| TETRA TECH EMC, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Nov 27, 2000 | Inactive |
| TETRA TECH RMC, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Jan 24, 2001 | Inactive |
| SCIENCES INTERNATIONAL, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Oct 4, 2001 | Inactive |
| GEMALTO COGENT, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | May 27, 2004 | Inactive |
| TETRA TECH ES, INC.Location not reported, FL · Inactive | Location not reported, FL | Corporation | Nov 10, 2004 | Inactive |