| Ladbrooke Junior Mixed and Infant School117370 | Primary | Good | 18.3% | 231 |
| Knutsford Primary Academy146123 | Primary | Good | 8.5% | 439 |
| Knightsfield School138485 | Not applicable | Outstanding | 24.2% | 73 |
| Knebworth Primary and Nursery School117120 | Primary | Good | 9.8% | 404 |
| Kingswood Nursery School117076 | Nursery | Outstanding | 0.0% | 93 |
| Kingsway Junior School117168 | Primary | Good | 27.5% | 236 |
| Kingsway Infants' School117317 | Primary | Good | 23.0% | 174 |
| Kingshott School117630 | Not applicable | — | — | 414 |
| Kingshill Infant School117319 | Primary | Good | 4.6% | 207 |
| Kings Langley School139036 | Secondary | Good | 13.6% | 1,104 |
| Kings Langley Primary School117283 | Primary | Good | 9.5% | 439 |
| King James Academy Royston137656 | All-through | Good | 19.6% | 939 |
| Kimpton Primary School117118 | Primary | Good | 14.7% | 145 |
| Killigrew Primary and Nursery School135528 | Primary | Good | 7.6% | 409 |
| Kenilworth Primary School117183 | Primary | Good | 28.0% | 220 |
| Katherine Warington School145890 | Secondary | Good | 15.4% | 1,017 |
| Jupiter Primary School140955 | Primary | Good | 22.0% | 410 |
| John F Kennedy Catholic School149743 | Secondary | Good | 13.9% | 1,078 |
| Jenyns First School and Nursery117087 | Primary | Good | 6.6% | 64 |
| James Marks Academy149736 | Not applicable | — | 19.5% | 51 |
| Immanuel College117657 | Not applicable | — | — | 446 |
| Icknield Walk First School117278 | Primary | Good | 8.9% | 345 |
| Icknield Infant and Nursery School117186 | Primary | Requires Improvement | 26.1% | 215 |
| Ickleford Primary School117401 | Primary | Good | 13.5% | 208 |
| Hurst Drive Primary School117180 | Primary | Good | 32.8% | 390 |
| Hunsdon Junior Mixed and Infant School117117 | Primary | Outstanding | 9.5% | 116 |
| Howe Dell Primary School117220 | Primary | Good | 14.8% | 439 |
| How Wood Primary and Nursery School117235 | Primary | Good | 14.0% | 223 |
| Hormead Church of England (va) First School117439 | Primary | Good | 13.4% | 131 |
| Homerswood Primary and Nursery School117252 | Primary | Good | 24.6% | 213 |
| Holy Trinity Church of England Primary School117428 | Primary | Good | 21.1% | 199 |
| Holy Rood Catholic Primary School146903 | Primary | Outstanding | 3.9% | 456 |
| Holwell Primary School117175 | Primary | Good | 32.3% | 406 |
| Holtsmere End Junior School117336 | Primary | Good | 35.8% | 229 |
| Holtsmere End Infant and Nursery School117377 | Primary | Good | 22.6% | 212 |
| Hollybush Primary School117263 | Primary | Requires Improvement | 35.8% | 204 |
| Holdbrook Primary School and Nursery117091 | Primary | Good | 44.1% | 205 |
| Hockerill Anglo-European College136482 | Secondary | Good | 4.3% | 926 |
| Hobletts Manor Junior School117097 | Primary | Good | 27.5% | 240 |
| Hobletts Manor Infants' School117197 | Primary | Good | 16.8% | 218 |
| Hobbs Hill Wood Primary School117368 | Primary | Good | 15.8% | 454 |
| Hitchin Girls' School137288 | Secondary | Outstanding | 8.1% | 1,356 |
| Hitchin Boys' School139154 | Secondary | Outstanding | 7.5% | 1,357 |
| Hillshott Infant School and Nursery117123 | Primary | Good | 25.8% | 209 |
| Hillmead Primary School117310 | Primary | Good | 16.6% | 226 |
| Highwood Primary School117089 | Primary | Good | 17.9% | 439 |
| Highover Junior Mixed and Infant School117115 | Primary | Outstanding | 7.0% | 434 |
| Highbury Infant School and Nursery117113 | Primary | Good | 7.7% | 214 |
| High Wych Church of England Primary School117398 | Primary | Good | 13.6% | 227 |
| High Leigh Primary School117270 | Primary | Requires Improvement | 40.3% | 154 |