Schools
O
| Name | Category | Notes |
|---|---|---|
| Oakbank School, Keighley | Comprehensive | |
| Oakham | Public School | |
| Oaklands RC Comprehensive School, Waterlooville | Comprehensive | |
| Oaklands Roman Catholic Comprehensive, Portsmouth | Comprehensive | |
| O'Connell Christian Brothers School, Dublin | Other Private | |
| Ogwen Grammar School | Grammar | |
| Old College, Homerton | dissenting ministry | |
| Old Cumnack Parish School, Ayrshire | Elementary | |
| Old Hall Green Sch, Herts | Other Private | |
| Oldham HS | Grammar | |
| Oldmeldrum Public School | Elementary | Not a 'public school' in the Headmasters' Conference sense. |
| Old Moat Primary School, Manchester | Primary School | |
| Old Palace School, Croydon | Independent | |
| Old Presbyterian College, Belfast | Other Private | |
| Old Swinford Hospital School | State boarding | |
| Olivers Mt School, Scarborough | Other Private | |
| Omagh Academy, Omagh | Grammar | |
| Oratory | Public School | P_F school |
| Oratory School | Other Private | |
| Oratory School, Birmingham | Public School |