| Tessy Automation | Pennsylvania |
| Test Equipment Connection | Florida |
| Test Force Corporation | New York |
| Test IO | |
| Test Yantra Global | |
| test.ai | California |
| Testco, Inc. | California |
| TESTCo, LLC | Texas |
| Tested Media | |
| TestEquity, LLC | California |
| TestFit, Inc. | Texas |
| TestFort | California |
| TestGrid | |
| Testim | |
| TestingXperts | Pennsylvania |
| Testive | |
| Testkube | |
| Testlio, Inc. | Texas |
| TestMatick Ltd | New York |
| Testmetrix, Inc. | California |
| TestMy.net | Texas |
| TestOut Corporation | Utah |
| TestPros | Virginia |
| testRigor | California |
| Testshop | Georgia |
| TestSight | California |
| Testsigma Technologies, Inc. | |
| TestSprite | Washington |
| Tesvan, LLC | |
| Tesvan, LLC | |
| Tether | New York |
| Tetherex Pharmaceuticals | |
| Tethernet, Inc. | Washington |
| Tethers Unlimited, Inc. | Washington |
| Tethr | Texas |
| Teton Data Systems | Wyoming |
| Teton Technology | Wyoming |
| Tetra Forza Soft | New Jersey |
| Tetra Trust Company | |
| Tetracode, LLC | |
| Tetracore, Inc. | Maryland |
| Tetrad Computer Applications, Inc. | Washington |
| Tetrad Digital Integrity | District of Columbia |
| TetraMem | |
| TetraScience, Inc. | Massachusetts |
| Tetrasoft, Inc. | Missouri |
| Tetrate | |
| Tetrous, Inc. | |
| TeuxDeux, LLC | New York |
| Tevard Biosciences | Massachusetts |