| Abbreviation | Definition |
|---|---|
| MSNA | Mississippi School Nurse Association |
| MSNA | Mississippi School Nutrition Association |
| MSNA | Missouri School Nutrition Association |
| MSPA | Maryland School Psychologists' Association |
| MSPA | Massachusetts School Psychologists Association |
| MSPA | Michigan Speedway Promoters Association |
| MSPA | Minnesota School Psychologists Association |
| MSPA | Mystery Shopping Providers Association's |
| MSPBA | Michigan State Polish Bowling Association |
| MSRA | Maryland Street Racing Association |
| MSRA | Michiana Soccer Referees Association |
| MSRA | Mid States Rodeo Association |
| MSRA | Midwest Scholastic Rowing Association |
| MSRA | Midwest Street Rod Association |
| MSSA | Maine School Superintendents Association |
| MSSA | Medical Student Society Association |
| MSSA | Medical Students Society and Association |
| MSSA | Memphis Sport Shooting Association |
| MSSA | Mid South Sign Association |
| MSSA | Minnesota Social Service Association |