| Ohio Valley Local CTPD, OH (District) |
| Ohio Virtual Academy, OH (PSA) |
| Oil City Area SD, PA (District) |
| Oilton, OK (District) |
| Ojai Unified, CA (District) |
| Ojibwe Charter School, MI (PSA) |
| Okaloosa, FL (District) |
| Okaloosa County, FL (ISD) |
| Okanogan County, WA (ISD) |
| Okanogan School District, WA (District) |
| Okarche, OK (District) |
| Okaw Area Vocational Center, IL (District) |
| Okaw Regional Voc System, IL (District) |
| Okaw Valley CUSD 302, IL (District) |
| Okay, OK (District) |
