St. Catharines Brands
- M&M Food Market (3)
- Magicuts (2)
- MANCHU WOK (1)
- Mandarin (1)
- Manitoulin Transport (1)
- Mappins Jewellers (1)
- Marbleslab Creamery (2)
- Mark's L'Équipeur (2)
- Marlin Travel (3)
- Mary Brown's (1)
- McDonald's (7)
- MEDIGAS (1)
- Melanie Lyne (1)
- Metro (1)
- MICHAELS (1)
- Midas (2)
- Minuteman Press International (1)
- Mister Transmission (2)
- MNP LTD (5)
- MONEY MART (5)
- MONTANA'S (1)
- Moores Clothing (1)
- Mr. Lube (1)
- MR.SUB (3)
- MS Society of Canada (1)