| Abbreviation | Definition |
|---|---|
| SSVA | Support Services of Virginia, Inc. |
| SSVDP | Society of St. Vincent de Paul |
| SSVDP-DET | Society of St. Vincent de Paul of Detroit |
| SSW | SweatShop Watch |
| St.JA | Saint John Ambulance |
| STAND | Shut This Airport Nightmare Down |
| STAND | Students Take Action for New Directions |
| STAND | Students Taking Action Now: Darfur |
| STAP | Subsequent Term Alignment Plan |
| STARFISH | Society Taking Active Responsibility For International Self Help |
| STARS | Shock Trauma Air Rescue Society |
| STB | Save The Bay |
| STBF | Susan Thompson Buffet Foundation |
| STCF | St Tammany Cancer Fund |
| STCP | Sumatran Tiger Conservation Program |
| STE | Save The Earth |
| STEP | Small Business Tax Education Center |
| STEPFAM | Stepfamily Association of America |
| STER | Stand to End Rape Initiative |
| STFAN | South Texas Family Aids Network |