VCO may refer to:

Military

  • Veterinary Corps Officer, see Veterinary corps (disambiguation)
  • Viceroy's commissioned officer, British Indian Army role (1885–1947)

Technology

  • Voltage-controlled oscillator, an electronic device
  • Voice Carry Over, a telecommunications relay service
  • Akatsuki (spacecraft), or the Venus Climate Orbiter
  • Virtual Central Office, in Open Platform for NFV network-function virtualization software

Other uses

  • Vegan Camp Out, an annual UK camping festival
  • Voyage Century Online, a nautically themed, free-to-play, massively multiplayer online role-playing game
  • Vice Commodore, an elected yacht club committee member
  • VCO SA, the joint-stock company, and a distributor of Volcano clothing brand