MSSU
| Acronym | Definition |
|---|---|
| MSSU | Missouri Southern State University (Joplin) |
| MSSU | Medical-Surgical Stepdown Unit (healthcare) |
| MSSU | Moscow State Social University |
| MSSU | Microsoft Services University |
| MSSU | Management Selection & Succession Unit (HM Prison Service; UK) |
| MSSU | Mid Stream Specimen Urine |
| MSSU | Mid Stream Sample of Urine |