| Abbreviation | Definition |
|---|---|
| THS | Titanic Historical Society |
| THSC | Toledo Hearing and Speech Center |
| THT | Terrance Higgins Trust |
| TIAF | The Interfaith Alliance Foundation |
| TIAW | The International Alliance for Women |
| TIC | The Information Center |
| TIDRC | Texas Illegal Dumping Resource Center |
| TIGHAR | The International Group for Historic Aircraft Recovery |
| TII | The Independent Institute |
| TILF | Texas Interscholastic League Foundation |
| TIMS | The International Molinological Society |
| TINS | Tahoe Institute for Natural Science |
| TIP | Technical Interest Profile |
| TIPC | Technical Institute of Physics and Chemistry |
| TIPC | Technical Interpretations Policy Committee |
| TIPC | Technology Integration Project Consortium |
| TIPC | The Injury Prevention Coalition |
| TIPS | Tobacco Information and Prevention Source |
| TIS | To Inspire Strong African Children Fund |
| TISS | Takakei Information System Society |