| Abbreviation | Definition |
|---|---|
| SGYF | South Gate Youth Football (South Gate, CA) |
| SHY | Supportive Housing for Youth |
| SITY | System Improvement Through Youth |
| SIYB | Spokane Indians Youth Baseball |
| SIYB | Stichting International Youth Bridges |
| SIYSS | Stockholm International Youth Science Seminar |
| SJYS | San Jose Youth Symphony |
| SKY | Saint Kilian Youththe |
| SKY | Saint Kilian Youth—the |
| SKY | Skilled Knowledgeable Youth |
| SKY | Stand for Kashmiri Youth |
| SKYC | Sno King Youth Club |
| SLAY | Self Love Acceptance for Youth |
| SLAY | Stage Left Acting Youth |
| SLAY | Student Leaders Among Youth |
| SLAY | Support Legal Advocacy for Youth |
| SLOVA | Slova means sleepover. It is mainly used in Ireland. |
| SLSYO | St Louis Symphony Youth Orchestra |
| SLY | Saint Lawrence Youth |
| SLY | Sheldon Little Youth |