| Abbreviation | Definition |
|---|---|
| SIP | Strategic and Institutional Plan |
| SIPRI | Stockholm International Peace Research Institute |
| SIPT | Sable Island Preservation Trust |
| SIR | Société Internationale Renardienne (International Reynard Society) |
| SIR | Société Internationale Renardienne (International Reynard Society) |
| SIR | Society of Interventional Radiology |
| SIRC | Social Issues Research Centre |
| SIS | Soccer In the Streets |
| SIT | School for International Training |
| SITC | State Information Technology Consortium |
| SJCRH | St. Jude Children's Research Hospital |
| SKAD | Steal Kill and Destroy |
| SKCC | Sidney Kimmel Cancer Center |
| SKF | Sujit Kumar Foundation |
| SKF | Sunshine Kids Foundation |
| SKI | Send A Kid To Israel |
| SKIPOFNY | Sick Kids need Involved People of New York |
| SKS | Swayam Krishi Sangam |
| SKSK | Used in TTY to notify the operator that they are hanging up the call (not an acronym) |
| SLA | Society for Location Analysis |