GCM
- Claremore Regional Airport
- GCM Resources
- Galois/Counter Mode
- General circulation model
- Genesis Climber MOSPEADA
- Global Campaign for Microbicides
- Global Compact for Migration
- Good Conduct Medal (United States)
- Google Cloud Messaging
- Grand Central Madison station
- Grand Corps Malade
- Grand Cross of the Order of Merit (Portugal)
- Great Central Mines
- Great Commission Ministries
- Greatest common measure
- Gross combination mass
- Ground continuity monitor
- Knight Grand Cross Royal Order of Monisaraphon
- Owen Roberts International Airport