| Abbreviation | Definition |
|---|---|
| MMDRA | Midwest Motorcycle Drag Racing Association |
| MMOR | Massively Multiplayer Online Racing |
| MMR | Mantaray Motorsport Racing |
| MMR | Modular Motorsports Racing |
| MMRA | Michigan Midget Racing Association |
| MMRT | Marquette Mountain Race Team |
| MMRT | Marquette Mountain Racing Team |
| MMRT | Micky Morris Racing Team |
| MMTC | Mid-Michigan Track Club |
| MMTR | Minnesota Monster Truck Racers |
| MMWW | Mark Martin Walt West |
| MOPAR | Move Over, People Are Racing |
| MORR | Midwest Off Road Racing |
| MORS | Masonman's Online Racing Series |
| MPR | Maximum Performance Racing |
| MR | Mitsu Racing |
| MR | Mitsubishi Racing |
| MRA | Motocross Racing Association |
| MRA | Motorcycle Roadracing Association |
| MRAN | Motorcycle Racing Association of Nevada |