| Merchant Taylors' School117616 | Not applicable | — | — | 1,051 |
| Merchant Taylors' Prep School117651 | Not applicable | — | — | 330 |
| Meadow Wood School117691 | Not applicable | Good | 28.6% | 36 |
| Mary Exton Primary School117329 | Primary | Good | 17.1% | 146 |
| Martins Wood Primary School149330 | Primary | Expected standard | 17.7% | 532 |
| Marriotts School117534 | Secondary | Expected standard | 31.9% | 1,415 |
| Markyate Village School and Nursery117127 | Primary | Good | 12.4% | 211 |
| Margaret Wix Primary School117188 | Primary | Good | 27.5% | 167 |
| Maple Primary School117298 | Primary | Expected standard | 6.5% | 214 |
| Maple Grove Primary School135221 | Primary | Requires Improvement | 33.5% | 206 |
| Maple Cross Junior Mixed Infant and Nursery School117266 | Primary | Good | 25.5% | 166 |
| Manor Lodge School117658 | Not applicable | — | — | 458 |
| Manor Fields Primary School144960 | Primary | Good | 6.7% | 449 |
| Manland Primary School117103 | Primary | Good | 3.4% | 204 |
| Mandeville Primary School117305 | Primary | Good | 14.3% | 318 |
| Mandeville Primary School139159 | Primary | Good | 29.1% | 340 |
| Malvern Way Infant and Nursery School117133 | Primary | Outstanding | 3.7% | 240 |
| Ludwick Nursery School117079 | Nursery | Outstanding | 0.0% | 177 |
| Loreto College138106 | Secondary | Outstanding | 14.8% | 952 |
| Lordship Farm Primary School117330 | Primary | Good | 8.0% | 447 |
| Lonsdale School117679 | Not applicable | Good | 34.9% | 128 |
| Longwood School117662 | Not applicable | — | — | 65 |
| Longmeadow Primary School135083 | Primary | Requires Improvement | 35.1% | 201 |
| Longlands Primary School and Nursery117326 | Primary | Outstanding | 26.9% | 217 |
| Longdean School137110 | Secondary | Good | 26.3% | 1,436 |
| Long Marston VA Church of England Primary and Nursery School117459 | Primary | Good | 19.8% | 130 |
| London Colney Primary & Nursery School117146 | Primary | Good | 34.7% | 156 |
| Lodge Farm Primary School132091 | Primary | Requires Improvement | 17.2% | 386 |
| Lockers Park School117611 | Not applicable | — | — | 152 |
| Lochinver House School117643 | Not applicable | — | — | 314 |
| Little Reddings Primary School137861 | Primary | Good | 33.1% | 312 |
| Little Munden Church of England Voluntary Controlled Primary School117402 | Primary | Good | 16.9% | 78 |
| Little Heath Primary School117567 | Primary | Good | 19.1% | 225 |
| Little Hadham Primary School117126 | Primary | Outstanding | 9.5% | 151 |
| Little Green Junior School117132 | Primary | Good | 6.6% | 346 |
| Little Gaddesden Church of England Voluntary Aided Primary School117443 | Primary | Good | 9.7% | 109 |
| Links Hatfield Academy147451 | Not applicable | Good | 50.0% | 16 |
| Links Academy139197 | Not applicable | Good | 70.0% | 10 |
| Lime Walk Primary School117333 | Primary | Good | 30.9% | 212 |
| Leverstock Green Church of England Primary School117416 | Primary | Good | 15.9% | 229 |
| Leventhorpe137156 | Secondary | Good | 12.6% | 1,463 |
| Letchmore Infants' and Nursery School117151 | Primary | Outstanding | 11.6% | 295 |
| Leavesden Jmi School117324 | Primary | Good | 28.3% | 389 |
| Layston Church of England First School117390 | Primary | Requires Improvement | 21.8% | 124 |
| Laureate Academy146440 | Secondary | Good | 39.1% | 703 |
| Laurance Haines School143603 | Primary | Good | 16.6% | 463 |
| Larwood School143604 | Not applicable | Good | 57.0% | 151 |
| Larkspur Academy146359 | Primary | Good | 60.0% | 64 |
| Lanchester Primary School140954 | Primary | Good | 13.1% | 298 |
| Lakeside School117680 | Not applicable | Outstanding | 29.2% | 115 |