ISU may refer to:
Schools United States Idaho State University, Pocatello, Idaho Illinois State University, Normal, Illinois Illinois State University (Springfield, Illinois) Indiana State University, Terre Haute, Indiana Iowa State University, Ames, Iowa
Elsewhere I-Shou University, Kaohsiung, Taiwan Ifugao State University, in the Philippines Ilia State University, in Tbilisi, Georgia Imo State University Ingush State University, in Magas, Republic of Ingushetia International School of Uganda, Kampala, Uganda International School of Ulaanbaatar, Mongolia International Solomon University, in Ukraine International Space University, Illkirch-Graffenstaden, France Irkutsk State University, in Eastern Siberia
Organizations ISU (trade union), British trade union formerly known as the Immigration Service Union Integrated Security Unit, in Canada Internal Security Unit, the counter-intelligence unit of the Provisional Irish Republican Army (IRA) International Seamen's Union International Skating Union
Other Italian Service Units, Italian prisoner of war army units that served on the Allied side during World War II ISU (singer) Isu language (Bantu), also called Suwu or Subu, a Bantu language of Cameroon Isu language, a Grassfields Bantu language of Cameroon Isu, Nigeria, a local government area of Imo State Isu people, an ethnic group in Nigeria Isu station, on the Seoul Metropolitan Subway ISU-152, ISU-122, Soviet self-propelled guns SAP IS-U, Industry Specific Solution for Utilities International System of Units, the SI system ISU, the IATA airport code for Sulaimaniyah International Airport, Iraq