| Oklahoma School For The Blind, OK (District) |
| Oklahoma School For The Deaf, OK (District) |
| Oklahoma Union, OK (District) |
| Oklee Public School District, MN (District) |
| Okmulgee, OK (District) |
| Okmulgee County, OK (ISD) |
| 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) |
