USFI
| 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) |