| Linchfield Academy147677 | Primary | Good | 22.5% | 307 |
| Lift Utterby139885 | Primary | Good | 25.0% | 68 |
| Lift North Thoresby139868 | Primary | Good | 20.2% | 99 |
| Leslie Manser Primary School120509 | Primary | Good | 42.7% | 262 |
| Legsby Primary School120457 | Primary | Good | 35.3% | 34 |
| Leadenham Church of England Academy149272 | Primary | Requires Improvement | 53.3% | 30 |
| Langtoft Primary School120381 | Primary | Good | 14.2% | 197 |
| Lacey Gardens Junior Academy146499 | Primary | Good | 57.8% | 315 |
| Kisimul School120740 | Not applicable | — | — | 74 |
| Kirton Primary School120415 | Primary | Good | 34.9% | 537 |
| Kirkstone House School120729 | Not applicable | — | — | 115 |
| King Edward Vi Grammar School142262 | Secondary | Good | 11.0% | 889 |
| King Edward Vi Academy138783 | Secondary | Good | 46.3% | 380 |
| Kidgate Academy138637 | Primary | Requires Improvement | 31.2% | 420 |
| Kesteven and Sleaford High School Selective Academy137667 | Secondary | Outstanding | 9.1% | 756 |
| Kesteven and Grantham Girls' School138638 | Secondary | Outstanding | 7.5% | 1,202 |
| Kelsey Primary School120469 | Primary | Good | 21.2% | 99 |
| Keelby Primary Academy141793 | Primary | Good | 23.3% | 180 |
| John Spendluffe Foundation Technology College136968 | Secondary | Good | 52.1% | 634 |
| Ingoldsby Academy141390 | Primary | Good | 20.8% | 72 |
| Ingoldmells Academy138444 | Primary | Good | 70.3% | 124 |
| Ingham Primary School120454 | Primary | Good | 11.9% | 84 |
| Huttoft Primary & Nursery School138808 | Primary | Good | 28.5% | 164 |
| Huntingtower Community Primary Academy139618 | Primary | Good | 38.8% | 417 |
| Horncastle Primary School148713 | Primary | Good | 38.8% | 430 |
| Holton-le-Clay Junior School120497 | Primary | Good | 24.8% | 109 |
| Holton Sleaford Independent School148356 | Not applicable | — | — | 79 |
| Holton Le Clay Infant School120453 | Primary | Good | 12.7% | 71 |
| Holbeach Primary Academy141260 | Primary | Good | 36.5% | 315 |
| Holbeach Bank Primary Academy145734 | Primary | Good | 53.9% | 90 |
| Hogsthorpe Primary Academy138749 | Primary | Good | 44.6% | 56 |
| Hemswell Cliff Primary School120491 | Primary | Good | 71.4% | 35 |
| Helpringham Primary Academy151091 | Primary | Good | 34.9% | 86 |
| Heighington Millfield Primary Academy137201 | Primary | Good | 13.8% | 210 |
| Heckington St Andrew's Church of England School120526 | Primary | Good | 31.6% | 158 |
| Heckington House School145932 | Not applicable | — | — | 33 |
| Hawthorn Tree School120424 | Primary | Good | 32.9% | 368 |
| Haven High Academy138754 | Secondary | Inadequate | 36.4% | 1,272 |
| Hartsholme Academy146559 | Primary | Good | 43.5% | 354 |
| Handel House Preparatory School120733 | Not applicable | — | — | 46 |
| Halton Holegate CofE Primary School120573 | Primary | Good | 45.0% | 60 |
| Grimoldby Primary School120684 | Primary | Good | 20.3% | 207 |
| Greenwich House School120743 | Not applicable | — | — | 94 |
| Greenfields Academy139316 | Not applicable | Good | 65.9% | 82 |
| Great Steeping Primary School120451 | Primary | Requires Improvement | 37.5% | 95 |
| Great Ponton Church of England School120602 | Primary | Good | 32.6% | 46 |
| Grasby All Saints Church of England Primary School120571 | Primary | Good | 22.8% | 79 |
| Grantham Preparatory International School120738 | Not applicable | — | — | 108 |
| Grantham College130759 | 16 plus | — | — | — |
| Grainthorpe Junior School120450 | Primary | Good | 44.4% | 45 |