GCGS
| Acronym | Definition |
|---|---|
| GCGS | Goncalves-Chauffage-Gaz-Services (French: Goncalves-Heating-Gas Services) |
| GCGS | Grand Chapitre des Grades de Sagesse (French: Grand Chapter Degrees of Wisdom) |
| GCGS | Galveston County Genealogical Society (Texas) |
| GCGS | Granville County Genealogical Society 1746 (est. 1994; North Carolina) |
| GCGS | Gaultois Cardinal General Services (Hammond, Ontario) |