GMT or Greenwich Mean Time is the mean solar time at the Royal Observatory in Greenwich, London.
GMT may also refer to:
Science and technology
- Generic Mapping Tools in graphical computing
- Geometric measure theory
- Giant Magellan Telescope, a telescope under construction in Chile 11
- GM GMT platform, an automobile platform
- Great Melbourne Telescope, built in Dublin, Ireland
Transport
- GATX, an American rolling stock leaser
- Granite Mountain Air Station, an airport in Alaska
- Greater Manchester Transport, in England
- Green Mountain Transit, a transportation company in Vermont
- Grosmont railway station, in England
Other uses
- GMT (TV programme), UK
- Glycine/sarcosine N-methyltransferase, an enzyme
- G:MT – Greenwich Mean Time, a 1999 British film
- GMT Games, US
- GMT Records, a Japanese record label
- Goodman–Martinez–Thompson correlation, between the Mayan and Julian calendars
- Guy McCoy Tormé, a British rock-band
- Metal-Textile Union, a former Austrian trade union
- Gregoria Mariska Tunjung, Indonesian female badminton player
