| Acronym | Definition |
|---|
| UMSA | Universidad Mayor de San Andrés (La Paz, Bolivia) |
| UMSA | Universities at Medway Students' Association (UK) |
| UMSA | United Muslim Students Association |
| UMSA | Udruzenje Muslimana Sjeverne Amerike (Serbian: Society of Bosnian Muslims of North America) |
| UMSA | Unincorporated Municipal Service Area |
| UMSA | Unreimbursed Medical Spending Account |
| UMSA | University Medical Services Association (Wright State University School of Medicine; Dayton, OH, USA) |
| UMSA | United Mini Sprint Association |
| UMSA | Unincorporated Metropolitan Services Area |
| UMSA | Upper Midwest Security Alliance |
| UMSA | Unity Movement of South Africa |
| UMSA | Unionville Minor Softball Association (Ontario, Canada) |
| UMSA | Universal Metallurgical Simulator and Analyzer |
| UMSA | Undergraduate Modeling, Simulation, and Analysis (course) |
| UMSA | Union of Malaysian Students in Auckland (New Zealand) |
| UMSA | Undergraduate Mathematics Students Association |
| UMSA | University of Manchester Staff Association (UK) |
| UMSA | United Methodist Student Association |
| UMSA | Ultrasound Manufacturers and Suppliers Association |
| UMSA | Uniform Money Services Act of 2000 (US) |
| UMSA | United Minority Students Association |
| UMSA | United Mobile Sportfishermen Association |
| UMSA | United Marine Suppliers Association, LLC (Springfield, MO) |
| UMSA | Usiminas Mecânica SA (Brazilian steel company) |
| UMSA | Universal Mating Service America |