| Abbreviation | Definition |
|---|---|
| GLOS | Gloucestershire County, England |
| GLOSA | Green Light Optimized Speed Advisory |
| GLS | Gear Lubricant Special |
| GLTB | Gloucestershire Local Transport Board |
| GM | General Malfunctions |
| GM | General Motors |
| GMC | General Motors Corporation |
| GMC | Get Motor Checked |
| GMCC | General NAS Maintenance Control Center |
| GMD | General Motors Diesel |
| GMDSS | Global Maritime Distress Safety System |
| GMH | Get Me to Hawaii |
| GMIS | Grants Management Information System |
| GMPTA | Greater Manchester Passenger Transport Authority |
| GMPTE | Greater Manchester Passenger Transport Executive |
| GMR | Glendora Mountain Road |
| GMSP | Georgia Motorcycle Safety Program |
| GMTA | Green Mountain Transit Agency |
| GMTS | Global Maritime Transportation Services |
| GNAS | General NAS |