ICO
- Catalan Ornithological Institute
- Cocos (Keeling) Islands
- ICO (file format)
- ICO Global Communications
- ICOS (disambiguation)
- IKO (disambiguation)
- Ico
- Ico Hitrec
- Ico, el caballito valiente
- Icó
- Illinois College of Optometry
- Index of Central Obesity
- Indian Computing Olympiad
- Information Commissioner's Office
- Initial coin offering
- Institute of Contemporary Observation
- Instituto de Crédito Oficial
- Intermediate circular orbit
- International Coffee Organization
- International Commission for Optics
- International Communist Opposition
- International Council of Ophthalmology
- Irish Chamber Orchestra
- Irish College of Ophthalmologists
- Israel Chamber Orchestra
- LC0 (disambiguation)