| LeRoyer, Ann | Master Plan Update Advisory Committee | | | |
| Lionetta, Anthony | Central School Feasibility Study Committee | Boards & Commissions | | |
| Liscio, Laura | Council on Aging, 2024 | | | |
| Lobel, Josh | Finance Committee (Prct. 8, 2025) | | | |
| Locke, Beth | Semiquincentennial Committee, Arlington Chamber of Commerce | | | |
| Logan, William | Election Modernization Committee, Board of Registrars | | | |
| Logan (D) , William | Board of Registrars, 2027 | Boards & Commissions | | |
| Loosian, Kate | High School Building Committee, Community Member | | | |
| Lucarelli, Stephanie | Information Technology Advisory Committee | Boards & Commissions, Town Manager | | |
| Luczai, Katie | Parking Advisory Committee, Planning | Town Manager | | |
| Luczai, Katie | Commission for Arts & Culture (ACAC), Economic Development Coordinator | | | |
| Luczai, Katie | Arlington Committee on Tourism & Economic Development | | | kluczai@town.arlington.ma.us |
| Lyons, William | Arlington Committee on Tourism & Economic Development | Boards & Commissions | | |
| Lyons, William | Arlington Committee on Tourism & Economic Development | | | |
| MacDonald (R), Ralph E. | Board of Registrars, 2026 | Town Manager | | |
| Magee, Alex | Audit Advisory Committee, Deputy Town Manager | Town Manager | | |
| Magee, Alex | Capital Planning Committee, Deputy Town Manager/Finance Director | | | |
| Maher, John | Cable Advisory Committee, Chair | | | |
| Maher, John | Building Committee (PTBC), 6/2025 | | | |
| Mahon, Diane | CDBG Subcommittee, Select Board | | | |
