| Acronym | Definition |
|---|
| ISU | International Skating Union (Switzerland) |
| ISU | Iowa State University |
| ISU | Issue |
| ISU | International Space University |
| ISU | Ilinois State University |
| ISU | Idaho State University |
| ISU | Indiana State University |
| ISU | Inspectoratul Pentru Situatii de Urgenta (Romanian: Inspectorate for Emergency Situations) |
| ISU | I-Shou University (Taiwan) |
| ISU | International School of Uganda |
| ISU | Independent Study Unit |
| ISU | Initial Set-Up (software) |
| ISU | Invalid Switch Use |
| ISU | Isdn Service Unit |
| ISU | Installshield Uninstall |
| ISU | Interlocuteur Social Unique (French: Single Social Contact) |
| ISU | Incident Support Unit |
| ISU | Imam Sadiq University (Tehran, Iran) |
| ISU | International Salvage Union |
| ISU | Information State Update (dialogue management) |
| ISU | Isabela State University (Philippines) |
| ISU | Irkutsk State University (Russia) |
| ISU | International Stereoscopic Union |
| ISU | Independent Steelworkers Union |
| ISU | Instructional Services Unit (various schools) |
| ISU | Integrated Sensor Unit (avionics) |
| ISU | Investigative Support Unit |
| ISU | Integrated Service Umbilical (pipe construction) |
| ISU | Investigative Services Unit |
| ISU | Involving Service Users (UK) |
| ISU | Integrated Sight Unit |
| ISU | Industry Specific Utilities |
| ISU | Integrated Service Unit |
| ISU | Iridium Subscriber Unit |
| ISU | International Seamen's Union |
| ISU | Intake Screening Unit |
| ISU | Infinite Spongy Universe |
| ISU | Internal Stability Unit |
| ISU | Indian Student Union |
| ISU | Internationale Socialisters Ungdom (Danish Political Movement) |
| ISU | Iowa Southern Utilities |
| ISU | International Survey Unit (PricewaterhouseCoopers; UK) |
| ISU | Internal Airlift/Helicopter Slingable-Container Unit |
| ISU | Instrument Simulator Unit |
| ISU | Integriertes Steuerungs- und Uberwachungssystem (communications profile) |
| ISU | Inquiry System Update |
| ISU | International System Unit |
| ISU | Internet System Update |
| ISU | Information Service and Use |