| Oa - Suffolk142820 | Not applicable | Good | 60.0% | 10 |
| Occold Primary School146173 | Primary | Good | 10.4% | 48 |
| Old Buckenham Hall School124873 | Not applicable | — | — | 190 |
| Old Newton Church of England Primary School143070 | Primary | Good | 15.7% | 70 |
| On Track Education Mildenhall127003 | Not applicable | — | — | 43 |
| One Sixth Form College142283 | 16 plus | — | 0.0% | 2,338 |
| OneSchool Global UK Colchester Campus134480 | Not applicable | — | — | 131 |
| Orford Church of England Primary School and Nursery150252 | Primary | Good | 29.8% | 47 |
| Ormiston Denes Academy139403 | Secondary | Good | 55.6% | 730 |
| Ormiston Endeavour Academy137674 | Secondary | Good | 31.5% | 739 |
| Ormiston Sudbury Academy138506 | Secondary | Requires Improvement | 32.9% | 679 |
| Orwell Park School124866 | Not applicable | — | — | 210 |
| Otley Primary School124602 | Primary | Good | 17.9% | 57 |
| Oulton Broad Primary School124676 | Primary | Outstanding | 19.8% | 373 |
| Paddocks Primary School124565 | Primary | Good | 17.8% | 185 |
| Pakefield High School146909 | Secondary | Good | 38.9% | 701 |
| Pakefield Primary School141640 | Primary | Good | 19.4% | 311 |
| Palgrave Church of England Primary School143071 | Primary | Good | 7.1% | 84 |
| Parkside Academy142801 | Not applicable | Good | 50.0% | 4 |
| Phoenix St Peter Academy141983 | Primary | Good | 50.5% | 107 |
| Piper's Vale Primary - A Paradigm Academy145118 | Primary | Good | 51.0% | 345 |
| Place Farm Primary Academy138161 | Primary | Good | 31.3% | 403 |
| Poplars Community Primary School145541 | Primary | Requires Improvement | 51.3% | 277 |
| Pot Kiln Primary School124536 | Primary | Good | 30.2% | 265 |
| Priory School137433 | Not applicable | Outstanding | 48.6% | 224 |
| Pushforward Primary School152350 | Not applicable | — | — | — |
| Pushforward Secondary School152344 | Not applicable | — | — | — |
| Ranelagh Primary School124645 | Primary | Good | 31.4% | 299 |
| Rattlesden Church of England Primary Academy142554 | Primary | Good | 16.8% | 137 |
| Ravensmere Infant School143491 | Primary | Good | 12.9% | 31 |
| Ravenswood Community Primary School151105 | Primary | Good | 28.3% | 416 |
| Red Oak Primary School140573 | Primary | Good | 43.0% | 437 |
| Redstone Hall School152347 | Not applicable | — | — | — |
| Rendlesham Primary School145795 | Primary | Good | 7.6% | 291 |
| Reydon Primary School141702 | Primary | Good | 27.7% | 184 |
| Ringsfield Church of England Primary School144849 | Primary | Good | 10.2% | 111 |
| Ringshall School147509 | Primary | Good | 17.1% | 117 |
| Risby Church of England Voluntary Controlled Primary School124712 | Primary | Good | 8.9% | 202 |
| Riverwalk School146418 | Not applicable | Good | 39.4% | 218 |
| Roman Hill Primary School145559 | Primary | Requires Improvement | 50.4% | 430 |
| Rose Hill Primary145540 | Primary | Good | 33.3% | 270 |
| Rougham Church of England Primary School145237 | Primary | Good | 12.6% | 191 |
| Royal Hospital School124889 | Not applicable | — | — | 545 |
| Rushmere Hall Primary School148414 | Primary | Good | 14.7% | 535 |
| Saint Felix School124868 | Not applicable | — | — | 244 |
| Samuel Ward Academy136322 | Secondary | Good | 17.4% | 1,152 |
| Sandlings Primary School124685 | Primary | Good | 3.7% | 82 |
| Saxmundham Primary School146494 | Primary | Good | 41.8% | 254 |
| Sebert Wood Community Primary School124682 | Primary | Good | 9.4% | 381 |
| Sexton's Manor Primary School150689 | Primary | Good | 23.9% | 175 |