| Acronym | Meaning |
| GCS | Gateway Computer System |
| GCS | Global Combat Ship (UK Royal Navy) |
| GCS | Government Contractor Services (various organizations) |
| GCS | Ground Combat Systems |
| GCS | Ground Communications System |
| GCS | Ground Control Shelter |
| GCS | Ground Control Site |
| GCS | Ground Control Squadron |
| GCS | Ground Control Station |
| GCS | Ground Control Surveillance |
| GCS | Groupement de Coopération Sanitaire (French: Health Grouping Cooperation) |
| GCS | Guidance Control Section |
| GCS | Guidance Control System |
| GCS | Guidance Cutoff Signal (US NASA) |
| GCS | Gun Computer System |