FSF explained

FSF can stand for:

; Organizations and activism

• Financial Stability Forum
• Flight Safety Foundation, an international organization acting to improve aviation safety.
• Free Software Foundation, non-profit corporation to support the free software movement, and in particular the GNU Project.
• Free Speech Fights, a series of labor-related conflicts in the early 20th century US

; Arts and entertainment

• The Magazine of Fantasy & Science Fiction, also abbreviated F&SF
• F. Scott Fitzgerald, American writer
• Folsom Street Fair
• Football Supporters' Federation
• Further Seems Forever, a rock band
• Fugitive Strike Force, a 2006 television series.