FDFI
| Acronym | Definition |
|---|---|
| FDFI | Fault Detection and Fault Isolation |
| FDFI | First Day-First Issue (stamps) |
| FDFI | Freunde des Flughafen Innsbruck (German: Friends of Innsbruck Airport; Innsbruck, Austria) |
| FDFI | Fronteer Development Finance, Inc. (est. 1998; Delaware) |
| FDFI | Flying Disc Federation of India |