GCB
- GCB (McDonald's)
- GCB (TV series)
- GCB Bank
- Gaming control board
- Generator circuit breaker
- Gilmore City–Bradgate Community School District
- Giro Commercial Bank
- Global Corruption Barometer
- Gloucestershire Cricket Board
- Glucocerebrosidase
- Grand Cross of the Order of the Bath
- Great Calcite Belt
- Green Camel Bell
- Groupe Communiste Burkinabè
- Guides Catholiques de Belgique