SMO or Smo may refer to:

• Smoothened, a gene that encodes a protein of the same name
• Spermine oxidase, an enzyme
• Styrene monooxygenase, an enzyme

• Sequential minimal optimization, an algorithm for training support vector machines
• Social media optimization
• Solar Monitoring Observatory, on the International Space Station
• SQL Server Management Objects for Microsoft SQL Server

• Sabhal Mòr Ostaig, a Scottish Gaelic-medium public college on the Isle of Skye
• Slovak Youth Orchestra

• SMO, IATA airport code for Santa Monica Airport, USA
• SMO, National Rail station code for South Merton railway station, London

• SMO, ITU country code for Samoa
• smo, ISO 639-3 code for the Samoan language
• Smo, former stage name of Sara Forsberg (born 1994), Finnish singer
• SMO, a character first appeared in the episode "Be More" of the animated series Adventure Time
• Senior Medical Officer, a rank in the British Royal Army Medical Corps
• Singapore Mathematical Olympiad, a mathematics competition
• Site management organization, a provider of services to an organization holding a clinical trial
• Social movement organization, a formal organization within a social movement
• Special military operation, the Russian government's name for the 2022 Invasion of Ukraine
• Super Mario Odyssey, a video game released for the Nintendo Switch