| City | County | 2026 Pop. ↓ |
|---|---|---|
| Malden | Middlesex County | 66,362 |
| Medford | Middlesex County | 59,790 |
| Marlborough | Middlesex County | 43,391 |
| Milford | Worcester County | 30,810 |
| Melrose | Middlesex County | 29,527 |
| Milton | Norfolk County | 28,491 |
| Marshfield | Plymouth County | 27,489 |
| Middleborough | Plymouth County | 25,312 |
| Mansfield | Bristol County | 24,289 |
| Marblehead | Essex County | 20,568 |
| Mashpee | Barnstable County | 15,376 |
| Millbury | Worcester County | 14,363 |
| Medway | Norfolk County | 13,872 |
| Medfield | Norfolk County | 13,262 |
| Maynard | Middlesex County | 10,670 |
| Middleton | Essex County | 9,802 |
| Millis | Norfolk County | 9,656 |
| Montague | Franklin County | 8,340 |
| Monson | Hampden County | 8,202 |
| Mattapoisett | Plymouth County | 6,868 |
| Merrimac | Essex County | 6,810 |
| Mendon | Worcester County | 6,510 |
| Manchester-by-the-Sea | Essex County | 5,478 |
| Marion | Plymouth County | 5,368 |
| Millville | Worcester County | 3,182 |
| Monterey | Berkshire County | 1,091 |
| Montgomery | Hampden County | 848 |
| Middlefield | Hampshire County | 391 |
| Mount Washington | Berkshire County | 153 |
| Monroe | Franklin County | 114 |