FSG
- Facility Solutions Group
- Falling sand game
- Farrar, Straus and Giroux
- Fellow of the Society of Genealogists
- Fenway Sports Group
- Finite state grammar
- Fishersgate railway station
- Flensburger Schiffbau-Gesellschaft
- Florida State Guard
- Fluorosilicate glass
- Focal segmental glomerulosclerosis
- Folkestone School for Girls
- Fortress Study Group
- Free Spirit Gathering
- Free Standards Group
- Frontier Services Group
- United States Federal Sentencing Guidelines