| Mary Mcleod Bethune Institute | 0.0 |
Special program emphasis | 3-12 | 45 | 8.0 | Nonsectarian |
| Pepperell Christian Academy | 3.9 |
Regular elementary or secondary | Pre-KG-12 | 29 | 5.5 | Baptist |
| Seven Hills At Groton | 4.3 |
Special education | 1-12 | 25 | 8.3 | Nonsectarian |
| Twin City Christian School | 6.1 |
Regular elementary or secondary | Pre-KG-12 | 191 | 12.2 | Baptist |
| Seven Hills Academy | 7.0 |
Special education | 4-12 | 60 | 14.6 | Nonsectarian |
| Applewild School | 8.4 |
Regular elementary or secondary | KG-9 | 282 | 7.8 | Nonsectarian |
| Nashoba Learning Group | 10.1 |
Special education | Pre-KG-11 | 40 | 0.8 | Nonsectarian |
| South Lancaster Academy And Browning Elementary | 13.4 |
Regular elementary or secondary | Pre-KG-12 | 237 | 15.0 | Seventh-Day Adventist |
| Lighthouse School | 13.6 |
Special education | Pre-KG-12 | 220 | 6.7 | Nonsectarian |
| Rfk Lancaster School | 13.6 |
Special education | 4-12 | 36 | 1.1 | Nonsectarian |
| Sterling Nursery School | 14.0 |
Special education | Pre-KG-Pre-KG | 3 | 0.8 | Nonsectarian |
| Riverside School | 15.8 |
Special education | 2-12 | 34 | 4.9 | Nonsectarian |
| Merrimack Schools | 16.8 |
Alternative/other | 5-12 | 55 | 2.5 | Nonsectarian |
| The Fenn School | 19.2 |
Regular elementary or secondary | 4-9 | 304 | 8.2 | Nonsectarian |
| Willow Hill School | 20.0 |
Special education | 6-12 | 60 | 3.4 | Nonsectarian |
| Hillside School | 20.1 |
Regular elementary or secondary | 5-9 | 139 | 6.0 | Nonsectarian |
| Cottage Hill Academy | 20.7 |
Special education | 6-12 | 32 | 4.0 | Nonsectarian |
| Melmark New England | 20.9 |
Special education | Ungraded-Ungraded | 108 | 1.5 | Nonsectarian |
| Fellowship Christian Academy | 23.1 |
Regular elementary or secondary | Pre-KG-12 | 108 | 10.8 | Christian (no specific denomination) |
| Devereux School | 23.6 |
Special education | 1-12 | 114 | 6.7 | Nonsectarian |
| St Ann's Home Inc | 23.8 |
Special education | Ungraded-Ungraded | 122 | 6.7 | Nonsectarian |
| Sudbury Valley School | 23.9 |
Special program emphasis | Ungraded-Ungraded | 165 | 16.7 | Nonsectarian |
| Fay School | 23.9 |
Regular elementary or secondary | 1-9 | 379 | 6.6 | Nonsectarian |
| Reed Academy | 23.9 |
Special education | Ungraded-Ungraded | 20 | 3.4 | Nonsectarian |
| Bancroft School | 24.5 |
Regular elementary or secondary | KG-12 | 562 | 7.7 | Nonsectarian |
| Mercy Centre | 24.8 |
Special education | Ungraded-Ungraded | 24 | 6.0 | Roman Catholic |
