FSL

FSL may refer to:

Language

• Filipino Sign Language
• Finnish Sign Language
• French Sign Language

Other uses

• Fast Simplex Link, a soft microprocessor bus
• Five Schools League, a Northeast United States prep school athletics league
• Fleet Support Limited, a British logistics company
• Florida State League, an American minor baseball league
• Fluid Science Laboratory, on the International Space Station
• FMRIB Software Library
• FM FSL, a rifle
• Folger Shakespeare Library in Washington, D.C., United States
• Forecast Systems Laboratory of the United States National Oceanic and Atmospheric Administration
• Fox Sports Live, an American television program
• Fraternitas Scintilla Legis, a Philippine fraternity
• Freescale Semiconductor, an American semiconductor manufacturer
• Free-space loss
• Friends' School, Lisburn, in Northern Ireland
• Function-spacer-lipid construct