| Abbreviation | Definition |
|---|---|
| TMSA | Texas Middle School Association |
| TMSF | Thurgood Marshall Scholarship Fund |
| TMSI | The Meriwether Society Inc |
| TMSI | Tropical Marine Science Institute |
| TMV | Thai Mueang Volunteers |
| TNA | Texas Nurses Association |
| TNA | Trigeminal Neuralgia Association |
| TNC | The Nature Conservancy |
| TNEC | Terwilliger Nature Education Center |
| TNEWR | Terwilliger Nature Education and Wildlife Rehabilitation |
| TNEWRC | Terwilliger Nature Education and Wildlife Rehabilitation Center |
| TNF | Tamil Nadu Foundation |
| TNFAMA | Tamil Nadu Fireworks and Amorces Manufacturer's Association |
| TNG | The Neighbourhood Group |
| TNO | The Neighbourhood Organization |
| TNS | The Natural Step |
| TNS | The Naturist Society |
| TNT | Towards No Tobacco |
| TNTT | Thieu Nhi Thanh The |
| TOH | Tribe Of Heart |