M
- Maaria – became part of the City of Turku in 1967
- Maxmo (Maksamaa) – consolidated with Vörå to form Vörå-Maxmo in 2007
- Mellilä – consolidated with Loimaa in 2009
- Merimasku – consolidated with Naantali in 2009
- Messukylä – became part of the City of Tampere in 1947
- Metsämaa – became part of Loimaan kunta in 1976
- Metsäpirtti – was lost to the USSR in 1944
- Mietoinen – became part of Mynämäki in 2007
- Mikkelin maalaiskunta – became part of the City of Mikkeli in 2001
- Mouhijärvi – consolidated with Äetsä and Vammala to form Sastamala in 2009
- Munsala – consolidated with Nykarleby in 1975
- Muolaa – was lost to the USSR in 1944
- Muurla – consolidated with Salo in 2009
- Muuruvesi – became part of Juankoski in 1971
- Mänttä – consolidated with Vilppula in 2009. At the same time, Vilppula was renamed as Mänttä-Vilppula.
Read more about this topic: Former Municipalities Of Finland