ICU may refer to:
- Intensive care unit, a special department of a hospital that treats severely ill patients
- International Components for Unicode, software libraries supporting internationalization
- Union Cycliste Internationale, the international cycling union
- Intersection Capacity Utilization, a measure of the capacity of a roadway intersection
Universities:
- Information and Communications University, a research university in Daejeon, South Korea
- International Christian University, a private university in Mitaka, Tokyo, Japan
- International Christian University – Kiev, a private university in Kiev, Ukraine
- Imperial College Union, the students union of Imperial College London
Politics:
- Industrial and Commercial Workers' Union, a South African political group from the 1920s
- International Clearing Union, a non-existent currency regulatory institution proposed in 1944
- Internationalist Communist Union, an international grouping of Trotskyist political parties
- Islamic Courts Union, an armed group of Sharia courts in Somalia
Music and films:
- Inner City Unit, a British hard edge/punk band
- I.C.U. (film), an unreleased Australian thriller starring Christian Radford