- GB - Great Britain
- GDO - Planning (General Development) Order (Northern Ireland) 1993
- GSM - Global System for Mobile Communications or Groupe Speciale Mobile
- Greenfield Sites - This term refers to previously undeveloped lands outside the existing urban areas/urban footprints of towns, villages and other small settlements. Greenfield sites are in most cases agricultural lands at the edge of settlements.
- Groundwater - Water below the surface of the ground in the saturation zone and in direct contact with the ground or subsoil.