| Ombudsman Educational Services Ltd. A Subsidiary Of Educati, AZ (District) |
| Omega Alpha Academy, AZ (District) |
| Omega Schools D.B.A. Omega Academy Inc., AZ (District) |
| Omro School District, WI (District) |
| Onaga-Havensville-Wheaton, KS (District) |
| Onalaska ISD, TX (District) |
| Onalaska School District, WI (District) |
| Onalaska School District, WA (District) |
| Onamia Public School District, MN (District) |
| Onaway Area Community School District, MI (District) |
| One City Preparatory Academy, WI (PSA) |
| One City Schools Inc, WI (PSA) |
| One City Senior Preschool, WI (PSA) |
| Oneida, WI (ISD) |
| Oneida, TN (District) |
