| Abbreviation | Definition |
|---|---|
| MRU | Marginal Revolution University |
| MRU | Miami Regional University |
| MRU | Mount Royal University |
| MRU | Muteesa i Royal University |
| MRU | Mykolas Romeris University |
| MRX | Magnetic Reconnection Experiment |
| MS | Mad Scientist |
| MS | Management Science |
| MS | Medical Student |
| MS | Meet Students |
| MS | Mississippi State |
| MS | Mortuary Science |
| MSA | Malaysian Students Association |
| MSA | Michigan Student Assembly |
| MSA | Minnesota Student Association |
| MSA | Minnesota Students Association |
| MSA | Minority Student Association |
| MSA | Missouri Students Association |
| MSA | Modern Sciences and Arts University |
| MSA | Monash Student Association |