| Abbreviation | Definition |
|---|---|
| MSEA | Mountain States Eventing Association |
| MSGA | Maryland State Golf Association |
| MSGA | Med Sense Guaranteed Association |
| MSGA | Medical Student Government Association |
| MSGA | Michiana Senior Golf Association |
| MSGA | Minnesota Soybean Growers Association |
| MSGA | Monitor Sugarbeet Growers Association |
| MSGA | Montana State Golf Association |
| MSGA | Montana Stock Growers Association |
| MSHRA | Master of Science in Human Resources Association |
| MSIA | Michigan Self Insurers' Association |
| MSIA | Missouri Self Insurers Association |
| MSLA | Mississippi Surplus Lines Association |
| MSLA | Montrose Softball League Association |
| MSLA | Multi State Lottery Association |
| MSMA | Minnesota Street Machine Association |
| MSMA | Mississippi State Medical Association |
| MSNA | Maine State Nurses Association |
| MSNA | Male Student Nursing Association |
| MSNA | Minority Student Nurses Association |