FCO may mean:

  • Foreign and Commonwealth Office, the United Kingdom's Ministry of Foreign Affairs
  • Ferro Carril Oeste, a football club of Buenos Aires and the eponymous railway
  • Financial Control Officer, a controller
  • Fort Collins, Colorado, the fifth most populated city in Colorado
  • Leonardo da Vinci-Fiumicino Airport, near Rome, Italy, by IATA airport code
  • Federal cartel office, German competition authority (Bundeskartellamt)