| South Lancaster Academy And Browning Elementary | 1.5 |
Regular elementary or secondary | Pre-KG-12 | 237 | 15.0 | Seventh-Day Adventist |
| Sterling Nursery School | 6.1 |
Special education | Pre-KG-Pre-KG | 3 | 0.8 | Nonsectarian |
| Hillside School | 6.8 |
Regular elementary or secondary | 5-9 | 139 | 6.0 | Nonsectarian |
| Seven Hills Academy | 7.0 |
Special education | 4-12 | 60 | 14.6 | Nonsectarian |
| Twin City Christian School | 11.1 |
Regular elementary or secondary | Pre-KG-12 | 191 | 12.2 | Baptist |
| Fay School | 11.4 |
Regular elementary or secondary | 1-9 | 379 | 6.6 | Nonsectarian |
| Bancroft School | 12.4 |
Regular elementary or secondary | KG-12 | 562 | 7.7 | Nonsectarian |
| Seven Hills At Groton | 12.5 |
Special education | 1-12 | 25 | 8.3 | Nonsectarian |
| Sudbury Valley School | 12.8 |
Special program emphasis | Ungraded-Ungraded | 165 | 16.7 | Nonsectarian |
| Reed Academy | 12.8 |
Special education | Ungraded-Ungraded | 20 | 3.4 | Nonsectarian |
| Applewild School | 12.9 |
Regular elementary or secondary | KG-9 | 282 | 7.8 | Nonsectarian |
| Willow Hill School | 12.9 |
Special education | 6-12 | 60 | 3.4 | Nonsectarian |
| Mercy Centre | 12.9 |
Special education | Ungraded-Ungraded | 24 | 6.0 | Roman Catholic |
| New England Center For Children | 13.0 |
Special education | Pre-KG-12 | 191 | 2.3 | Nonsectarian |
| Mary Mcleod Bethune Institute | 13.6 |
Special program emphasis | 3-12 | 45 | 8.0 | Nonsectarian |
| Nashoba Learning Group | 14.5 |
Special education | Pre-KG-11 | 40 | 0.8 | Nonsectarian |
| Yeshiva Achei Tmimim Academy | 14.5 |
Regular elementary or secondary | Pre-KG-12 | 86 | 4.2 | Jewish |
| Worcester Academy | 14.7 |
Regular elementary or secondary | 6-12 | 631 | 8.9 | Nonsectarian |
| The Learning Center For The Deaf | 15.0 |
Special education | Pre-KG-12 | 184 | 4.3 | Nonsectarian |
| G Stanley Hall School | 15.1 |
Special education | 3-12 | 43 | 6.1 | Nonsectarian |
| Kathleen Burns Preparatory School | 15.2 |
Special education | 5-12 | 36 | 5.1 | Nonsectarian |
| Pepperell Christian Academy | 15.6 |
Regular elementary or secondary | Pre-KG-12 | 29 | 5.5 | Baptist |
| Devereux School | 15.9 |
Special education | 1-12 | 114 | 6.7 | Nonsectarian |
| The Fenn School | 15.9 |
Regular elementary or secondary | 4-9 | 304 | 8.2 | Nonsectarian |
| Archway Inc | 17.2 |
Special education | 5-12 | 13 | 4.5 | Nonsectarian |
| Touchstone Community School | 17.8 |
Alternative/other | Ungraded-Ungraded | 129 | 10.4 | Nonsectarian |
| Brandon Residential Treatment | 18.4 |
Special education | 1-11 | 74 | 5.9 | Nonsectarian |
| Crossroad Center For Children | 18.6 |
Special education | Ungraded-Ungraded | 40 | 5.7 | Nonsectarian |
| The Rivers School | 19.0 |
Regular elementary or secondary | 6-12 | 433 | 7.5 | Nonsectarian |
| Merrimack Schools | 19.7 |
Alternative/other | 5-12 | 55 | 2.5 | Nonsectarian |
| Lighthouse School | 19.8 |
Special education | Pre-KG-12 | 220 | 6.7 | Nonsectarian |
| The Gifford School | 20.1 |
Special education | 4-12 | 106 | 4.8 | Nonsectarian |
| Community Therapeutic Day School Inc | 20.9 |
Special education | Ungraded-Ungraded | 30 | 2.6 | Nonsectarian |
| Evergreen Center | 21.3 |
Special education | Ungraded-Ungraded | 89 | 6.8 | Nonsectarian |
| Cotting School | 21.6 |
Special education | Ungraded-Ungraded | 119 | 4.8 | Nonsectarian |
| Dana Hall School | 21.6 |
Regular elementary or secondary | 6-12 | 485 | 9.2 | Nonsectarian |
| Riverside School | 21.7 |
Special education | 2-12 | 34 | 4.9 | Nonsectarian |
| Learning Prep School | 22.7 |
Special education | Ungraded-Ungraded | 403 | 2.8 | Nonsectarian |
| Fessenden School | 23.0 |
Regular elementary or secondary | KG-9 | 482 | 7.3 | Nonsectarian |
| Stetson School | 23.1 |
Special education | 4-12 | 111 | 6.9 | Nonsectarian |
| Clearway School | 23.1 |
Special education | 6-12 | 25 | 2.8 | Nonsectarian |
| Whitinsville Christian School | 23.2 |
Regular elementary or secondary | Pre-KG-12 | 551 | 13.1 | Calvinist |
| Valley View School | 23.5 |
Alternative/other | Ungraded-Ungraded | 56 | 4.7 | Nonsectarian |
| Protestant Guild For Human Services | 23.6 |
Special education | Ungraded-Ungraded | 60 | 6.1 | Nonsectarian |
| Protestant Guild Learning Center | 23.6 |
Special education | 5-12 | 38 | 2.3 | Nonsectarian |
| Cottage Hill Academy | 23.7 |
Special education | 6-12 | 32 | 4.0 | Nonsectarian |
| Lexington Christian Academy | 23.8 |
Regular elementary or secondary | 6-12 | 345 | 9.9 | Christian (no specific denomination) |
| Oak Hill Christian School | 24.1 |
Regular elementary or secondary | Pre-KG-9 | 30 | 5.9 | Christian (no specific denomination) |
| Germaine Lawrence | 24.2 |
Alternative/other | 6-12 | 50 | 4.5 | Nonsectarian |
| Newton Country Day School | 24.9 |
Regular elementary or secondary | 5-12 | 394 | 5.6 | Roman Catholic |
