| Acronym | Definition |
|---|
| FSF | Free Software Foundation |
| FSF | Fédération Sénégalaise de Football (French: Senegalese Football Federation; Senegal) |
| FSF | Financial Stability Forum |
| FSF | Flight Safety Foundation |
| FSF | File System Factory |
| FSF | Further Seems Forever (band) |
| FSF | Finished Square Feet (realty) |
| FSF | Financial-Services Firm |
| FSF | Forum de Stabilité Financière (French: Financial Stability Forum) |
| FSF | Florida State Fair (Tampa, FL) |
| FSF | Frequency-Selective Fading |
| FSF | Florida Sports Foundation |
| FSF | Foreign Security Force |
| FSF | Fédération des Stomisés de France (French: Ostomy Federation of France) |
| FSF | Fuel Storage Facility |
| FSF | Firefighters Support Foundation (Greenfield, MA) |
| FSF | Fourth Suit Forcing (bridge game) |
| FSF | The Magazine of Fantasy and Science Fiction |
| FSF | Fibrin Stabilizing Factor |
| FSF | Facilities Security Force (various locations) |
| FSF | Families Supporting Families |
| FSF | Footballeurs sans Frontières (French: Football Players without Borders) |
| FSF | Friends of Science Fiction |
| FSF | Fiscales Sin Fronteras (Spanish: Public Prosecutors Without Borders) |
| FSF | First Strike Force (gaming clan) |
| FSF | File System Factory (software) |
| FSF | Fótbóltssamband Føroya (Faroe Islands Football Association) |
| FSF | Federation Sim Fleet (Star Trek role playing and simming organization) |
| FSF | Fast Sea Frame |
| FSF | Fédération Sud Finance (French: South Finance Federation) |
| FSF | First Serve Fault (Tennis) |
| FSF | First Step Fund (Kansas City, MO) |
| FSF | Forward Sioux Falls (Sioux Falls, SD) |
| FSF | Frequency Scaling Factor |
| FSF | Finlands Svenska Folkdansring (Swedish: Finnish Swedish Folkdance Ring) |
| FSF | Folder-Staging Facility (Social Security) |
| FSF | Forward Support Facility |
| FSF | Female Seeking Female (personal ads) |
| FSF | Firearms Storage Facility |
| FSF | Flexible Storage Facility |
| FSF | Freiwillige Selbstkontrolle Fernsehen eV |
| FSF | Frederiksberg Skøjteløberforening (Denmark) |
| FSF | Flight Simulation Forum (website) |