| Acronym | Sense | Language | Topics |
|---|---|---|---|
| OSI | Open Systems Interconnection | In English | |
| OSI | Otto-Suhr-Institut für Politikwissenschaft | In German | → Politics |
| OSI | Open Source Initiative | In English | → Software |
| OSI | Open Society Institute | In English | → Politics → Fundamental rights |
| OSI | Office of Strategic Influence | In English | |
| OSI | Ordnance Survey Ireland | In English | → Republic of Ireland |
| OSI | Österreichisches Ost- und Südosteuropa-Institut (www.osi.ac.at) | In German | → Research institutes → Area studies → Austria |
| OSI | Onze Sport Inspireert | In Dutch | → Organizations and associations → Sport, physical exercises |