| ThoughtEater | Florida |
| ThoughtForm, Inc. | Pennsylvania |
| Thoughtful Automation | Illinois |
| Thoughtful NY, LLC | New York |
| Thoughtful Systems, Inc. | New York |
| Thoughtkeg Application Services, Inc. | |
| ThoughtLab, LLC | Utah |
| Thoughtline Digital Design | Wyoming |
| Thoughtly, Inc. | New York |
| Thoughtprocess Interactive | Missouri |
| ThoughtSpot, Inc. | California |
| ThoughtTrace, Inc. | Texas |
| Thoughtworks, Inc. | Illinois |
| Thouroughbred Innovations | |
| ThousandEyes, Inc. | California |
| Thrasio | Massachusetts |
| Thread | |
| Thread & Pixel, LLC | |
| Thread AI, Inc. | |
| Thread Group, Inc. | California |
| Thread Magic, Inc. | |
| Thread Marketing Group | Ohio |
| Threads | Iowa |
| Threat Informant | Alaska |
| Threat Reduction Solutions, LLC | Virginia |
| Threat Stack, Inc. | Washington |
| ThreatBlockr | Virginia |
| ThreatConnect, Inc. | Virginia |
| ThreatLocker, Inc. | |
| ThreatMark | North Carolina |
| Threatpost, Inc. | Massachusetts |
| ThreatQuotient, Inc. | Virginia |
| ThreatStop, Inc. | California |
| Three Colts Group, Inc. | Delaware |
| Three D Graphics, Inc. | California |
| Three Five Two, Inc. | Florida |
| Three Lakes Marketing, LLC | Texas |
| Three Point Turn | |
| Three Sixty Group | |
| Three Squared, Inc. | |
| Three Ventures Technology, Inc. | |
| Three Vistas | |
| Three29 Media, LLC | |
| ThreeCell | |
| Threekit, Inc. | Illinois |
| ThreeSixtyEight | Louisiana |
| Threespot | |
| ThreeTree, LLC | Virginia |
| Threshold | California |
| Thrifty Planet | Texas |