GMI
- Complex regional pain syndrome
- GMInsideNews
- GamesMaster International
- Gasmata Airport
- Gemini (protocol)
- General Mills
- General Motors Institute of Technology
- Genomic Medicine Institute
- George C. Marshall Institute
- Georgia Medical Institute
- Georgia Military Institute
- German-Malaysian Institute
- Germania (airline)
- Giant magnetoimpedance
- Global Methane Initiative
- Global Militarization Index
- Global Precipitation Measurement
- Global microbial identifier
- Gond Umri railway station
- Gorgas Memorial Institute for Health Studies
- Grace Ministries International
- Greater Ministries International
- Greenwich Maritime Institute
- Gregor Mendel Institute
- Groupement Mixte d'Intervention
- Guaranteed minimum income