| Acronym | Definition |
|---|
| MSSI➣Medical Staffing Solutions, Inc. (various locations) |
| MSSI➣Materials and Surface Science Institute (University of Limerick; Ireland) |
| MSSI➣Mexican Social Security Institute (est. 1943) |
| MSSI➣Mont Saint-Sauveur International (French; Canadian ski resort company) |
| MSSI➣Master of Science of Strategic Intelligence |
| MSSI➣Ministry of Small Scale Industries (India) |
| MSSI➣Management Systems Services, Inc. |
| MSSI➣Microsoft Shared Source Initiative (Microsoft Corporation) |
| MSSI➣Model State Statute Initiative |
| MSSI➣Measuring Stability and Security in Iraq (US DoD documentation) |