M
- (Simcoe County) McMurchy Settlement
- (Parry Sound District) McMurrich
- (Lanark County) McNaughton Shore
- (United Counties of Leeds and Grenville) McReynolds
- (United Counties of Leeds and Grenville) McRoberts Corner
- (Bruce County) McVicar
- (Ottawa) Mechanicsville
- (Oxford County) Medina
- (Simcoe County) Medonte
- (Dufferin County) Melancthon
- (Middlesex County) Melrose
- (Hastings County) Melrose
- (Perth County) Mennonite Corner
- (Simcoe County) Menoke Beach
- (Ottawa) Merivale
- (Ottawa) Merivale Gardens
- (Simcoe County) Mertz's Corner
- (Perth County) Metropolitan
- (Wellington County) Metz
- (Manitoulin District) Michael's Bay
- (Renfrew County) Micksburg
- (Elgin County) Middlemarch
- (Middlesex County) Middlemiss
- (Simcoe County) Midhurst
- (Simcoe County) Midhurst Station
- (Parry Sound District) Midlothian
- (Timiskaming District) Milberta
- (Frontenac County) Milburn
- (Elgin County) Mile Corner
- (Algoma) Milford Haven