| internal migration | migrazione interna |
| Internal motion | Moti interni |
| Internal Revenue | gettito fiscale |
| internal-combustion engine | motore a combustione interna |
| internalisation of external costs | internalizzazione dei costi |
| international | internazionale |
| International Agency for Research on Cancer | IARC |
| international agreement | accordo internazionale |
| International agreement or convention | Trattato internazionale |
| International Air Transport Association | International Air Transport Association |
| International Air Transport Association airport code | Codice aeroportuale IATA |
| International Alphabet of Sanskrit Transliteration | Alfabeto internazionale per la translitterazione del sanscrito |
| international assistance | aiuto internazionale |
| International Association of Athletics Federations | IAAF |
| International Association of Exorcists | Associazione internazionale degli esorcisti |
| International Association of Nitrox and Technical Divers | International Association of Nitrox and Technical Divers |
| International Astronomical Union | Unione Astronomica Internazionale |
| International Astronomical Youth Camp | International Astronomical Youth Camp |
| International Atomic Energy Agency | Agenzia Internazionale per l'Energia Atomica |
| International Atomic Time | Tempo atomico internazionale |
| International auxiliary language | Lingua ausiliaria internazionale |
| International Auxiliary Language Association | International Auxiliary Language Association |
| international balance | equilibrio internazionale |
| International Bank Account Number | International Bank Account Number |
| International Bank for Reconstruction and Development | Banca Internazionale per la Ricostruzione e lo Sviluppo |
| International Basketball Federation | Federazione Internazionale Pallacanestro |
| International Biathlon Union | International Biathlon Union |
| International Bible Students Association | Studenti della Bibbia |
| International Brigades | Brigate internazionali |
| International Bureau for the Revolutionary Party | Bureau Internazionale per il Partito Rivoluzionario |
