ICG
- American Morse code
- Defence Intelligence Staff
- Eclipse Comics
- ICG Communications
- ICG plc
- IIS University
- Icelandic Coast Guard
- Illinois Central Gulf Railroad
- Impedance cardiography
- Incitement to commit genocide
- Indian Coast Guard
- Indocyanine green
- Institute of Cosmology and Gravitation, University of Portsmouth
- Integrated clock gating
- International Children's Games
- International Cinematographers Guild
- International Coal Group
- International Composers' Guild
- International Crisis Group
- Internet Capital Group
- Inversive congruential generator
- Irish Continental Group
- United Nations Office for Outer Space Affairs