Schools
O
| Name | Category | Notes |
|---|---|---|
| Ormskirk Grammar School | Grammar | |
| Orsett House | Other private | Essex. |
| Oscott College | Public | |
| Oundle School | Public | |
| Ounsdale School | Comprehensive | |
| Our Lady and St Francis Secondary School | Comprehensive | Glasgow. |
| Our Lady and St Patrick's College | Grammar | Knock. |
| Our Lady and St Patrick's High School | Comprehensive | Dunbarton. |
| Our Lady's High School | Grammar | Motherwell. |
| Oxford High School | Grammar | |
| Oxford House School | Unknown | Chelsea. |
| Oxford Military College | FE college | |
| Oxted School | Grammar |