| Mansoura Students Scientific Association | Academic & Science |
| Multi Service Storage Architecture | Academic & Science |
| Medical Students Society and Association | Academic & Science |
| Montreal Student Space Associations | Academic & Science |
| Master of Science in Social Administration | Academic & Science |
| Microscopy Society of Southern Africa | Academic & Science |
| MA Student Services Administration | Academic & Science |
| Mid South Sociological Association | Business |
| Maryland Saltwater Sportfishermens Association | Business |
| Malaysian Singaporean Students Association | Business |
| Mormon Social Science Association | Business |
| Mssamanoa School Student Association | Business |
| Multiple Sclerosis Services Agency | Business |
| Minnesota State Student Association | Community |
| Montessori School of San Antonio | Community |
| Maine School Superintendents Association | Community |
| Memphis Sport Shooting Association | Community |
| Missouri Sport Shooting Association | Community |
| Minnesota Social Service Association | Community |
| Middlesex School Summer Arts | Community |
| Mid South Sign Association | Community |
| Microsoft Software Systems Academy | Computing |
| Monteagle Sunday School Assembly | Computing |
| Microsoft Software and Systems Academy | Computing |
| Master Supplier Services Agreement | Computing |
| Microsoft South Africa | Computing |
| More Super Soaker Action | General |
| Multi Sensor Surveillance Aircraft | General |
| Methicillin Susceptible S Aureus | General |
| Master Service and Supply Agreement | General |
| Methicillin-Sensitive Staphylococcus Aureus | General |
| Methicillin Susceptible Staphylococcus Aureus | General |
| methicillin sensitive S aureus | General |
| Meticillin sensitive Staphylococcus aureus | General |
| Mount Sinai Sailing Association | General |
| Methicillin Sensitive Staph Aureus | General |
| Mikuni Shimokawa Seishun Anime | General |
| Multiclass Spatial Stagewise Aggregation | General |
| Methicillin Susceptible Strains Abbreviation | General |
| Methicillin sensitive staph and | General |
| Mess Specialist Seaman Apprentice | Governmental |
| Military Selective Service Act | Governmental |
| Military-Style Semi-Automatic | Governmental |
| Mess Management Specialist Seaman Apprentice | Governmental |
| Medical Service Study Areas | Medical |
| Medical Student Society Association | Medical |
| Methicillin-Ausceptible Staphylococcus Aureus | Medical |
| Mountain States Stockdog Association | Regional |
| Montana Shooting Sports Association | Sports |
| Mind Sports South Africa | Sports |
| Maryland State Soccer Association | Sports |
| Maryland State Sportsmen's Association | Sports |
