| Acronym | Definition |
|---|
| USFI➣United Secretariat of the Fourth International |
| USFI➣Unione Stampa Filatelica Italiana (Italian: Italian Philatelic Press Union) |
| USFI➣United States Financial Institution |
| USFI➣Unmarried and Separated Fathers of Ireland (support group) |
| USFI➣United States Forces-Iraq (US DoD) |