FSO
FSO is an abbreviation for:
- Fabryka Samochodów Osobowych, Polish carmaker
- Familia Spiritualis Opus, Roman Catholic movement
- Well Sluzhba ochrany Federal, State Russian security services for the protection of the President and the Government
- Federazija Sportiwnowo Orijentirowanija Rossii, the Russian Orienteering Federation
- Feldberg school, vocational school in Oberursel (Taunus )
- Floating Storage and Offloading Vessel, in the offshore oil production as a storage and transfer station Ship, see Floating Production Storage and Offloading Unit
- Free-Space Optics technology for transmitting usually digital data by means of light, see Space Optics
- Disambiguation
- Abbreviation