| Sigel Township S/D #4F, MI (District) |
| Sigel Township S/D #6, MI (District) |
| Sigma Academy for Leadership and Early Middle College, MI (PSA) |
| Signal Hill SD 181, IL (District) |
| Signature School Inc, IN (District) |
| Sigourney Comm School District, IA (District) |
| Sikeston R-6, MO (District) |
| Silex R-I, MO (District) |
| Silo, OK (District) |
| Siloam Springs School District, AR (District) |
| Silsbee ISD, TX (District) |
| Silver Bow, MT (District) |
| Silver Bow County, MT (ISD) |
| Silver Consolidated Schools, NM (District) |
| Silver Creek Central School District, NY (District) |
