FSL
- FM FSL
- FMRIB Software Library
- Fast Simplex Link
- Fiji Senior League
- Filipino Sign Language
- Finnish Sign Language
- Fleet Support Limited
- Florida State League
- Fluid Science Laboratory
- Folger Shakespeare Library
- Forecast Systems Laboratory
- Fox Sports Live
- Fraternitas Scintilla Legis
- Free-space loss
- Freescale Semiconductor
- French Sign Language
- Friends' School, Lisburn
- Function-spacer-lipid construct