| Okoboji Comm School District, IA (District) |
| Okolona Separate School Dist, MS (District) |
| Oktaha, OK (District) |
| Oktibbeha County, MS (ISD) |
| Oktibbeha County School District, MS (District) |
| Olathe, KS (District) |
| Old Adobe Union, CA (District) |
| Old Bridge Township School District, NJ (District) |
| Old Brook High School, OH (PSA) |
| Old Colony Regional Vocational Technical, MA (District) |
| Old Forge SD, PA (District) |
| Old Fort Local School District, OH (District) |
| Old Mission Peninsula School, MI (PSA) |
| Old National Trail Spec Serv Coop, IN (District) |
| Old Redford Academy, MI (PSA) |
