M
- Mantus Anchors
- March Pumps
- Marco
- Marinco
- Marine Business
- Marine Hardware
- Marine Hydraulics
- Marine Tex
- Marine Works by Sierra
- Martyr Anodes
- MaryKate
- Master Lock
- Mastervolt
- Mate - USA
- Maxima
- Maxwell Winches
- McCloskey
- McDermott Light & Signal
- McGard
- McKay Shrimp & Crab Gear
- McMurdo
- McNett Corporation
- MDR
- Meeder Equipment
- Megaware KeelGuard
- Meguiar's
- Melling
- Mer-Maids Products
- Merrell
- Michigan Propeller
- Midland Metal Mfg. Co.
- Midland Radio Corporation
- Mighty Mag
- Minn Kota
- Minus 33
- Mirka
- Moeller
- Mora of Sweden
- Morse Industries
- Morse Marine Bearings
- MotorGuide
- Mpowerd
- Mr. Heater
- Muck Boot Company
- Mustad
- Mustang Survival
- Madison Bay Trading Company
- MTM Molded Products