IEP
- Icahn Enterprises
- Immunoelectrophoresis
- Inclusion–exclusion principle
- Independent Expert Panel
- Individualized Education Program
- Institute for Economics and Peace
- Institute for European Politics
- Institute for Political Studies – Catholic University of Portugal
- Institute of Employability Professionals
- Instituts d'études politiques
- Integrated electric propulsion
- Intercity Express Programme
- Internet Encyclopedia of Philosophy
- Irish pound
- Isoelectric point