GTS may stand for:
- HSV GTS, an Australian high-performance vehicle based on the Holden Commodore
- General Theological Seminary, a seminary in New York
- Geologic Time Scale, a system of chronological measurement
- Green Tobacco Sickness, a type of nicotine poisoning
- Greenwich Time Signal, a series of radio signals used to mark the precise start of an hour
- Gilles de la Tourette syndrome, a disorder characterized by motor and verbal tics
- Gas turbine ship, a naval vessel powered by gas turbines
- Great Trigonometric Survey, the first comprehensive survey of India to utilise triangulation.
- Global Telecommunications System, a network for the transmission of meteorological data
- Global Trade Station, a location in the Pokémon Diamond, Pearl, Platinum, HeartGold, and SoulSilver games that allows users to trade Pokémon with other users of the same via the Nintendo Wi-Fi Connection. Likewise, users of the Pokémon Black and White games can trade with other users via a similar but separate system with the same name.
- Go to Sleep, an attack used in professional wrestling.
- GTS/BKN, the callsign of a TV station known on-air as Southern Cross Television in Port Pirie, South Australia
- Grand Touring Supreme, a class in the IMSA GT Championship
- Geelong Transit System, a public transport brand in Geelong, Victoria, Australia
- GTS Technologies, a United Kingdom mechanical handling and paint finishing company.