| Acronym | Definition |
|---|
| IMSA | Illinois Mathematics and Science Academy |
| IMSA | Insurance Marketplace Standards Association |
| IMSA | International Motor Sports Association |
| IMSA | Interscan Messaging Security Appliance |
| IMSA | International Municipal Signal Association |
| IMSA | InterScan Messaging Security Appliance (Trend Micro) |
| IMSA | Iterative Multi-Scaling Approach (microwave theory) |
| IMSA | Incident Medical Specialist Assistant |
| IMSA | Isuzu Manufacturing Services of America (Plymouth, MI) |
| IMSA | Illinois Mini Storage Association |
| IMSA | Institute of Marine Safety Auditors |
| IMSA | Installation Medical Supply Account |
| IMSA | Integrated Medical Sciences Assessment (UK) |
| IMSA | Installation Medical Support Activity |
| IMSA | Seaman Apprentice, Instrumentman Striker (Naval Rating) |