FSO

FSO may refer to:

Government

 * Federal Protective Service (Russia) (Russian: Federalnaya Sluzhba Okhrany), responsible for the security of Russian state officials
 * Federal Statistical Office (Switzerland)
 * Financial Secretary's Office, of the Government of Hong Kong
 * Foreign Service Officer, of the United States Foreign Service
 * Forest Section Officer, in India

Music

 * Fairfax Symphony Orchestra, in Virginia, United States
 * Frankston Symphony Orchestra, in Victoria, Australia
 * Fulham Symphony Orchestra, in London
 * "F.S.O.", the first single from the Regurgitator album Tu-Plang
 * Film Symphony Orchestra, Czech classical orchestra

Transport

 * Fabryka Samochodów Osobowych, a Polish automotive company
 * Franklin County State Airport, in Vermont, United States
 * Subiaco railway station, in Western Australia

Other uses

 * Fire Support Officer
 * Flash shared object
 * Floating storage and offloading
 * Free-space optical communication
 * Flag Service Organization