| International Business Machines Corporation | IBM |
| International Color Consortium | International Color Consortium |
| International Correspondence Chess Federation | ICCF |
| International Earth Rotation and Reference Systems Service | International Earth Rotation and Reference Systems Service |
| International English Language Testing System | International English Language Testing System |
| International Financial Reporting Standards | International Accounting Standards |
| International Gamers Awards | International gamers award |
| International Gamma-Ray Astrophysics Laboratory | INTEGRAL |
| International Lesbian and Gay Association | Ilga |
| International Mobile Equipment Identity | International Mobile Equipment Identity |
| International Mobile Subscriber Identity | IMSI |
| International Music Score Library Project | International Music Score Library Project |
| International standard bibliographic description | International Standard Bibliographic Description |
| International Tennis Hall of Fame | International Tennis Hall of Fame |
| Internationale communiste | Comintern |
| Internationale des fédérations anarchistes | International of Anarchist Federation |
| Internationale démocrate centriste | Internazionale Democratica Centrista |
| Internationale Nederlanden Groep | ING Group |
| Internationale ouvrière | Seconda Internazionale |
| Internationale socialiste | Internazionale Socialista |
| Internationalisation | Internazionalizzazione e localizzazione |
| Internationalisation de logiciel | Internazionalizzazione e localizzazione |
| internationaliser | internazionalizzare |
