| Acronym | Meaning |
| ISU | Incident Support Unit |
| ISU | Inspectoratul Pentru Situatii de Urgenta (Romanian: Inspectorate for Emergency Situations) |
| ISU | Integrated Sensor Unit (avionics) |
| ISU | Integrated Sight Unit |
| ISU | Interlocuteur Social Unique (French: Single Social Contact) |
| ISU | Internal Airlift/Helicopter Slingable-Container Unit |
| ISU | Internal Stability Unit |
| ISU | Investigative Support Unit |
| ISU | Issue |