| Abbreviation | Definition |
|---|---|
| FISH | Followers In Service of Him |
| FISH | Friends In Service Helping |
| FISH | Friends In Service to Him |
| FITW | Faith In The Word Christian Center |
| FITW | Faith In The Workplace |
| FIWT | Faith in Worthless Things |
| FJ | Fort Jesus |
| FJCU | Fu Jen Catholic University |
| FKUB | Forum Kerukunan Umat Beragama (Indonesian: Religious Harmony Forum) |
| FKUB | Forum Komunikasi Umat Buddha (People of Buddhist Forum Communications; Jakarta, Indonesia) |
| FLAG | Fun Learning About God |
| FLASH | First Lutheran After-School Happening |
| FLCF | Family Life Christian Fellowship |
| FLCF | Family Life Christian Fellowship's |
| FLCF | First Light Christian Fellowship |
| FLCP | First Lutheran Children's Programs |
| FLCPA | First Lutheran Church, Palo Alto |
| FLCS | Finger Lakes Christian School |
| FLDS | Fundamental Latter Day Saints |
| FLDS | Fundamentalist Latter Day Saints |