FSY
| Acronym | Definition |
|---|---|
| FSY | For the Strength of Youth (Church of Jesus Christ of Latter-Day Saints) |
| FSY | Farrar, Straus and Young (publishing; now Farrar, Straus and Giroux) |
| FSY | Forsys Metals Corp (uranium exploration; Toronto, Ontario, Canada) |
| FSY | Fédération Suisse de Yoga (French: Swiss Yoga Federation) |
| FSY | Frame Sync |