STO may refer to:

  • Seoul Tourism Organization The Seoul Tourism Organization
  • Service du travail obligatoire, a forced labour programme introduced by the Vichy French government during World War II
  • Slater-type orbital, a function used to describe atomic orbitals in quantum chemistry
  • Société de transport de l'Outaouais, a public transit operator in Gatineau, Quebec, Canada
  • Sojourner Truth Organization, a defunct American leftist group
  • Soldiers of the One, a monotheistic religious group in Syfy's Caprica
  • Space Tornado Ogawa, a professional wrestling throw
  • SportsTime Ohio, a regional sports network in northeast Ohio, United States
  • Star Trek Online, a massively multiplayer online role-playing game
  • State Trading Organization, a publicly owned Maldivian company
  • Statoil, a publicly traded Norwegian oil company
  • STO-nG basis sets, the minimal basis sets in numeric quantic chemistry
  • STO - Brooklyn-based artist
  • Stockholm-All Airports, IATA airport code for Stockholm, Sweden including Arlanda Airport (ARN), Skavsta Airport (NYO), Bromma Airport (BMA), Västerås Airport (VST)
  • Stoney language (ISO 639-3 code)
  • Strontium titanate (SrTiO3)