ISU may refer to:
- International System of Unit
- ISU-152, ISU-122, Soviet self-propelled guns
- Integrated Security Unit
- International Skating Union
- International Seamen's Union
- International Stereoscopic Union
- Independent Study Unit
- Information State Update - a common approach to Dialogue system management.
- Industry Specific Solution for Utilities, an SAP solution
- ISU, a Union for the Border Agency (formerly called the Immigration Service Union), a union for immigration officers in the UK Border Agency
- ISU, the IATA airport code for Sulaimaniyah International Airport, Iraq
- Isu Station on the Seoul Metropolitan Subway
- Isu, Nigeria, a local government area of Imo State
- Isu language, a Grassfields Bantu language of Cameroon
- Isu language (Bantu), also called Suwu or Subu, a Bantu language of Cameroon
- Isu people, an ethnic group in Nigeria
- Isu, the yoruba word for Yam
- Isu, Cameroon, a town
Universities:
- Idaho State University, Pocatello, Idaho
- Illinois State University, Normal, Illinois
- Indiana State University, Terre Haute, Indiana
- International Space University, Illkirch-Graffenstaden, France
- Iowa State University, Ames, Iowa
Schools:
- International School of Ulaanbaatar, Mongolia
Student Union of India:
- Indian Student Union, Jharkhand, India