| Abbreviation | Definition |
|---|---|
| TPRG | Tuscaloosa Paranormal Research Group |
| TPRH | Turning Point Red Hook |
| TQF | Teaching Quality Foundation |
| TRANS | Transgender Radical Action Networking and Support |
| TRAPS | Texas Recreation and Parks Society |
| TRAV | Therapeutic Riding Association of Virginia |
| TRDF | The Red Door Foundation |
| TREA | The Retired Enlisted Association |
| TREAMF | The Retired Enlisted Association Memorial Foundation |
| TREF | Trauma Research and Education Foundation |
| TREI | The Renewable Energy Intiative |
| TREK | Transforming, Restoring, Establishing Kingdom life |
| TRF | The Rotary Foundation |
| TRIAD | Team Response Indians Against Defamation |
| TRIO | Transplant Recipients International Organization |
| TRTC | Triangle Rails-to-Trails Conservancy |
| TRUST | Teaching, Referral, Understanding, Support, and Testing |
| TSA | The Salvation Army |
| TSA | Tourette Syndrome Association |
| TSA | Tuberous Sclerosis Alliance |