ISU
- I-Shou University
- ISU (singer)
- ISU (trade union)
- ISU-122
- ISU-152
- Idaho State University
- Ifugao State University
- Ilia State University
- Illinois State University
- Illinois State University (Springfield, Illinois)
- Imo State University
- Indiana State University
- Ingush State University
- Integrated Security Unit
- Internal Security Unit
- International School of Uganda
- International School of Ulaanbaatar
- International Seamen's Union
- International Skating Union
- International Solomon University
- International Space University
- International System of Units
- Iowa State University
- Irkutsk State University
- Isu language
- Isu language (Bantu)
- Isu people
- Isu station
- Isu, Nigeria
- Italian Service Units
- SAP IS-U
- Sulaimaniyah International Airport