| Tank Design (Cambridge, MA) |
| TBWA (worldwide) |
| TBWA\Tequila (Los Angeles, CA) |
| Templin Brink Design (San Francisco, CA) |
| Think Interactive (Atlanta, GA) |
| Threespot Media (Washington, DC) |
| TMarks (Seattle, WA) |
| TM Advertising (Irving, TX) |
| Torque Ltd. (Chicago, IL) |
| TractorBeam (Dallas, TX) |
| Turner & Associates (San Francisco, CA) |
| Turner Duckworth (San Francisco, CA. London, UK) |
| Twenty Free (Philadelphia, PA) |
| Typebox, LLC (San Francisco, CA) |