| ISU | I Screwed Up 
| Others |
| ISU | I Support Usagi
| Others |
| ISU | Idaho State University
| Others |
| ISU | IGBT Supply Unit
| Others |
| ISU | Ill-a-noise State University
| Others |
| ISU | Ill-and-noisey Soviet University
| Others |
| ISU | Illinois Socialist University
| Others |
| ISU | Illinois State University
| Others |
| ISU | Imam Sadiq University
| Others |
| ISU | In Situ Update
| Others |
| ISU | In Stat Ua
| Others |
| ISU | Incident Support Unit
| Others |
| ISU | Independant Study Unit
| Others |
| ISU | Independent Site Unit
| Others |
| ISU | Independent Study Unit
| Others |
| ISU | Independent Studying Unit
| Others |
| ISU | Indiana State University
| Others |
| ISU | Industrial Solution Utilities
| Others |
| ISU | Industry Solution Units
| Others |
| ISU | Information Services Unlimited
| Others |
| ISU | Installshield Uninstall
| Others |
| ISU | Institutional Services Unit
| Others |
| ISU | Instrument Switching Unit
| Others |
| ISU | Insurance and Superannuation Unit
| Others |
| ISU | Integrated Semantic Unit
| Others |
| ISU | Integrated Service Unit
| Others |
| ISU | Intelligent Switch Unit
| Others |
| ISU | Intelligent Switching Unit
| Others |
| ISU | Interactive Superinduce Unit
| Others |
| ISU | Internal Airlift / Helicopter Slingable Container Unit
| Others |
| ISU | Internal Airlift or Helicopter Slingable Container Unit
| Others |
| ISU | Internal Stability Unit
| Others |
| ISU | International Skating Union
| Others |
| ISU | International Space University
| Others |
| ISU | International Stereoscopic Union
| Others |
| ISU | International Student Union
| Others |
| ISU | International Students Union
| Others |
| ISU | International Swindlers Union
| Others |
| ISU | International System of Units
| Others |
| ISU | Internet Services Unit
| Others |
| ISU | Invalid Switch Use
| Others |
| ISU | Inverter Safety Unit
| Others |
| ISU | Investigation And Surveillance Units
| Others |
| ISU | Investigative Support Unit
| Others |
| ISU | Iowa Service and Upgrade
| Others |
| ISU | Iowa Southern Utilities (Southern Industrial Railroad)
| Others |
| ISU | Iowa State University
| Others |
| ISU | Isabela State University
| Others |
| ISU | Isdn Service Unit
| Others |
| ISU | Isuzu
| Others |