| Merchant Taylors' School117616 | Not applicable | — | — | 959 |
| Merchant Taylors' Prep School117651 | Not applicable | — | — | 365 |
| Meadow Wood School117691 | Not applicable | Good | 27.8% | 37 |
| Mary Exton Primary School117329 | Primary | Good | 16.5% | 170 |
| Martins Wood Primary School149330 | Primary | Inadequate | 13.7% | 587 |
| Marriotts School117534 | Secondary | Good | 31.3% | 1,410 |
| Markyate Village School and Nursery117127 | Primary | Good | 11.8% | 220 |
| Margaret Wix Primary School117188 | Primary | Good | 34.0% | 148 |
| Maple Primary School117298 | Primary | Good | 5.6% | 215 |
| Maple Grove Primary School135221 | Primary | Requires Improvement | 28.7% | 210 |
| Maple Cross Junior Mixed Infant and Nursery School117266 | Primary | Good | 21.7% | 164 |
| Manor Lodge School117658 | Not applicable | — | — | 463 |
| Manor Fields Primary School144960 | Primary | Good | 6.2% | 447 |
| Manland Primary School117103 | Primary | Good | 3.0% | 203 |
| Mandeville Primary School117305 | Primary | Good | 11.8% | 282 |
| Mandeville Primary School139159 | Primary | Good | 27.4% | 366 |
| Malvern Way Infant and Nursery School117133 | Primary | Outstanding | 5.2% | 261 |
| Ludwick Nursery School117079 | Nursery | Outstanding | 0.0% | 174 |
| Loreto College138106 | Secondary | Outstanding | 14.1% | 930 |
| Lordship Farm Primary School117330 | Primary | Good | 7.0% | 446 |
| Lonsdale School117679 | Not applicable | Good | 38.2% | 129 |
| Longwood School117662 | Not applicable | — | — | 37 |
| Longmeadow Primary School135083 | Primary | Requires Improvement | 30.8% | 206 |
| Longlands Primary School and Nursery117326 | Primary | Outstanding | 29.5% | 217 |
| Longdean School137110 | Secondary | Good | 25.9% | 1,443 |
| Long Marston VA Church of England Primary and Nursery School117459 | Primary | Good | 18.2% | 140 |
| London Colney Primary & Nursery School117146 | Primary | Good | 26.7% | 175 |
| Lodge Farm Primary School132091 | Primary | Requires Improvement | 19.3% | 412 |
| Lockers Park School117611 | Not applicable | — | — | 189 |
| Lochinver House School117643 | Not applicable | — | — | 324 |
| Little Reddings Primary School137861 | Primary | Good | 30.6% | 327 |
| Little Munden Church of England Voluntary Controlled Primary School117402 | Primary | Good | 13.2% | 79 |
| Little Heath Primary School117567 | Primary | Good | 17.6% | 234 |
| Little Hadham Primary School117126 | Primary | Outstanding | 13.4% | 139 |
| Little Green Junior School117132 | Primary | Good | 5.1% | 355 |
| Little Gaddesden Church of England Voluntary Aided Primary School117443 | Primary | Good | 8.8% | 102 |
| Links Hatfield Academy147451 | Not applicable | Good | 46.7% | 15 |
| Links Academy139197 | Not applicable | Good | 60.0% | 10 |
| Lime Walk Primary School117333 | Primary | Good | 31.7% | 211 |
| Leverstock Green Church of England Primary School117416 | Primary | Good | 15.9% | 233 |
| Leventhorpe137156 | Secondary | Good | 10.8% | 1,471 |
| Letchmore Infants' and Nursery School117151 | Primary | Outstanding | 10.3% | 308 |
| Leavesden Jmi School117324 | Primary | Good | 27.6% | 408 |
| Layston Church of England First School117390 | Primary | Requires Improvement | 21.6% | 139 |
| Laureate Academy146440 | Secondary | Good | 36.7% | 746 |
| Laurance Haines School143603 | Primary | Good | 16.3% | 468 |
| Larwood School143604 | Not applicable | Good | 58.1% | 117 |
| Larkspur Academy146359 | Primary | Good | 57.8% | 87 |
| Lanchester Primary School140954 | Primary | Good | 14.4% | 334 |
| Lakeside School117680 | Not applicable | Outstanding | 30.3% | 112 |