| Abbreviation | Definition |
|---|---|
| MSL | Mids Sussex League |
| MSN | Mountaineer Sports Network |
| MSO | Mind Sport Olympiad |
| MSO | Mind Sports Olympiad |
| MSP | Massive Single Player |
| MSP | Midwest Sports Productions |
| MSP | Most Sporting Player |
| MSR | Manomet Street Racer |
| MSR | motor sports racing |
| MSRA | Metropolitan Squash Racquets Association |
| MSRA | Mid-States Rodeo Association |
| MSSA | Maryland State Soccer Association |
| MSSA | Maryland State Sportsmen's Association |
| MSSA | Montana Shooting Sports Association |
| MSSC | Madison Sports and Social Club |
| MSSC | Molinara Sports Social Club |
| MSST | Midnight Sun Swim Team |
| MST | Majestic Sports Turf |
| MSTO | Missouri State Tae-kwon-do Organization |
| MSURC | Michigan State University Racing Club |