| Acronym | Definition |
|---|
| GMT | Greenwich Mean Time |
| GMT | Giant Magellan Telescope |
| GMT | Generic Mapping Tools (software) |
| GMT | Global Mean Temperature |
| GMT | Global Mixed-Mode Technology (est. 1996; Taiwan) |
| GMT | General Motors Trucks |
| GMT | Generic Mapping Tools |
| GMT | Gigabyte Management Tools |
| GMT | Geometric Mean Titer (vaccination) |
| GMT | Greenwich Meridian Time |
| GMT | Geometric Mean Titers |
| GMT | Guy, McCoy, Torme (band) |
| GMT | General Military Training |
| GMT | Glass Mat Thermoplastic |
| GMT | Governor Macquarie Tower (Sydney, Australia) |
| GMT | Gunner's Mate (Technician, USN Rating) |
| GMT | Global Management Technologies |
| GMT | Good Management Practice |
| GMT | Ground Moving Target |
| GMT | Get Me Tickets |
| GMT | Gear Media Tech (Pixel Corps) |
| GMT | General Motors Tandem (diesel) |
| GMT | Ground Multiband Terminal |
| GMT | Groupe Multidisciplinaire Sur l'action Internationale Contre Le Terrorisme (French: Multidisciplinary Group on International Action against Terrorism, EC) |
| GMT | Global Media Transfer (Harris Automation) |
| GMT | Gannett, McClatchy and Tribune (ad network) |
| GMT | George Massey Tunnel (British Columbia, Canada) |
| GMT | Glasgow Museum of Transport (Scotland) |
| GMT | Green Metric Ton |
| GMT | Generalized Multi-Pole Technique |
| GMT | Guided Missile Transport |
| GMT | General Map Table |
| GMT | Glen Moore Transportation, Inc. |
| GMT | GACT Multiterminal |
| GMT | Guided Missile Target |