19 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Lowell city | Middlesex County | 114,506 |
| Lynn city | Essex County | 101,965 |
| Lawrence city | Essex County | 88,624 |
| Leominster city | Worcester County | 43,385 |
| Lexington town | Middlesex County | 33,942 |
| Ludlow town | Hampden County | 20,817 |
| Longmeadow town | Hampden County | 15,621 |
| Lynnfield town | Essex County | 13,198 |
| Lakeville town | Plymouth County | 12,114 |
| Lunenburg town | Worcester County | 11,831 |
| Leicester town | Worcester County | 11,076 |
| Littleton town | Middlesex County | 10,369 |
| Lancaster town | Worcester County | 9,588 |
| Lincoln town | Middlesex County | 6,891 |
| Lee town | Berkshire County | 5,642 |
| Lenox town | Berkshire County | 5,048 |
| Lanesborough town | Berkshire County | 2,973 |
| Leverett town | Franklin County | 1,851 |
| Leyden town | Franklin County | 725 |