| Hobletts Manor Infants' School117197 | Primary | Good | 16.8% | 218 |
| Hobletts Manor Junior School117097 | Primary | Good | 27.5% | 240 |
| Hockerill Anglo-European College136482 | Secondary | Good | 4.3% | 926 |
| Holdbrook Primary School and Nursery117091 | Primary | Good | 44.1% | 205 |
| Hollybush Primary School117263 | Primary | Requires Improvement | 35.8% | 204 |
| Holtsmere End Infant and Nursery School117377 | Primary | Good | 22.6% | 212 |
| Holtsmere End Junior School117336 | Primary | Good | 35.8% | 229 |
| Holwell Primary School117175 | Primary | Good | 32.3% | 406 |
| Holy Rood Catholic Primary School146903 | Primary | Outstanding | 3.9% | 456 |
| Holy Trinity Church of England Primary School117428 | Primary | Good | 21.1% | 199 |
| Homerswood Primary and Nursery School117252 | Primary | Good | 24.6% | 213 |
| Hormead Church of England (va) First School117439 | Primary | Good | 13.4% | 131 |
| How Wood Primary and Nursery School117235 | Primary | Good | 14.0% | 223 |
| Howe Dell Primary School117220 | Primary | Good | 14.8% | 439 |
| Hunsdon Junior Mixed and Infant School117117 | Primary | Outstanding | 9.5% | 116 |
| Hurst Drive Primary School117180 | Primary | Good | 32.8% | 390 |
| Ickleford Primary School117401 | Primary | Good | 13.5% | 208 |
| Icknield Infant and Nursery School117186 | Primary | Requires Improvement | 26.1% | 215 |
| Icknield Walk First School117278 | Primary | Good | 8.9% | 345 |
| Immanuel College117657 | Not applicable | — | — | 446 |
| James Marks Academy149736 | Not applicable | — | 19.5% | 51 |
| Jenyns First School and Nursery117087 | Primary | Good | 6.6% | 64 |
| John F Kennedy Catholic School149743 | Secondary | Good | 13.9% | 1,078 |
| Jupiter Primary School140955 | Primary | Good | 22.0% | 410 |
| Katherine Warington School145890 | Secondary | Good | 15.4% | 1,017 |
| Kenilworth Primary School117183 | Primary | Good | 28.0% | 220 |
| Killigrew Primary and Nursery School135528 | Primary | Good | 7.6% | 409 |
| Kimpton Primary School117118 | Primary | Good | 14.7% | 145 |
| King James Academy Royston137656 | All-through | Good | 19.6% | 939 |
| Kings Langley Primary School117283 | Primary | Good | 9.5% | 439 |
| Kings Langley School139036 | Secondary | Good | 13.6% | 1,104 |
| Kingshill Infant School117319 | Primary | Good | 4.6% | 207 |
| Kingshott School117630 | Not applicable | — | — | 414 |
| Kingsway Infants' School117317 | Primary | Good | 23.0% | 174 |
| Kingsway Junior School117168 | Primary | Good | 27.5% | 236 |
| Kingswood Nursery School117076 | Nursery | Outstanding | 0.0% | 93 |
| Knebworth Primary and Nursery School117120 | Primary | Good | 9.8% | 404 |
| Knightsfield School138485 | Not applicable | Outstanding | 24.2% | 73 |
| Knutsford Primary Academy146123 | Primary | Good | 8.5% | 439 |
| Ladbrooke Junior Mixed and Infant School117370 | Primary | Good | 18.3% | 231 |
| Lakeside School117680 | Not applicable | Outstanding | 30.3% | 112 |
| Lanchester Primary School140954 | Primary | Good | 14.4% | 334 |
| Larkspur Academy146359 | Primary | Good | 57.8% | 87 |
| Larwood School143604 | Not applicable | Good | 58.1% | 117 |
| Laurance Haines School143603 | Primary | Good | 16.3% | 468 |
| Laureate Academy146440 | Secondary | Good | 36.7% | 746 |
| Layston Church of England First School117390 | Primary | Requires Improvement | 21.6% | 139 |
| Leavesden Jmi School117324 | Primary | Good | 27.6% | 408 |
| Letchmore Infants' and Nursery School117151 | Primary | Outstanding | 10.3% | 308 |
| Leventhorpe137156 | Secondary | Good | 10.8% | 1,471 |