FI
- .fi
- Bourne shell
- FEI (disambiguation)
- Falkland Islands
- Fast Infoset
- Fecal incontinence
- Fee-fi-fo-fum
- Feminist Initiative (Sweden)
- Fi (TV series)
- Fi (The Legend of Zelda)
- Fi (letter)
- Fie (disambiguation)
- Films Incorporated
- Financial Institution
- Financial Supervisory Authority (Sweden)
- Finland
- Finnish language
- Fiona Hammond
- Forza Italia (disambiguation)
- Fourth International
- Franciscans International
- Freudenthal Institute
- Front de l'Indépendance
- Fuel injection
- Google Fi Wireless
- High fidelity (disambiguation)
- Icelandair
- La France Insoumise
- Lo-fi (disambiguation)
- Phi
- Province of Firenze
- Solfège