OTS may refer to:

• Anacortes Airport in Anacortes, Washington by IATA airport code
• Oakley Training School, a juvenile correctional facility in Hinds County, Mississippi
• Ocean Therapy Solutions, a company owned by actor Kevin Costner that develops centrifuge pumps for oceanic oil spill cleanup
• Octadecyltrichlorosilane, a chemical forming self-assembled monolayers
• Off the shelf, a term referring to a product currently being designed and manufactured
• Office of Tax Simplification a new body set up by the United Kingdom Treasury
• Office of Thrift Supervision, a U.S. Treasury Department agency that used to supervise Savings and loan associations until it was merged with the Office of the Comptroller of the Currency
• Officer Training School, United States Air Force
• Officer Training School RAAF, Royal Australian Air Force
• Open Two Seater a British term for a roadster car
• Opportunity to see, a measure of the impact of advertising
• Orchestra at Temple Square, an LDS orchestra located in Salt Lake City
• Organization for Tropical Studies, which operates a network of biological research stations
• Order of the Solar Temple, a sectarian group
• Oudtestamentische studiën, a theological journal
• Over the shoulder, a film technique
• Tosylate, the anion of p-toluenesulfonic acid (written as OTs or TsO)

The Izh (; , Otš; ) is a river in Udmurtia and Tatarstan, Russian Federation, a right-bank tributary of the Kama River. Its length is 226 km (97 of them in Tatarstan) and its drainage basin is 8,478 km². It origins near Malye Oshvortsy,Udmurtia and falls to the Nizhnekamsk Reservoir, Kama River near Golyushurma tract in Agryzsky District, Tatarstan.