QG may mean:
- Quantum gravity, a physics theory unifying relativity (gravity) and quantum mechanics
- Queen's Gambit, a chess opening move
- Quasigeostrophic, an atmospheric dynamics theory - see Geostrophic wind
- Quadrature Generator, see Quadrature amplitude modulation
- Quake God, a level in the PC game
- Nissan QG engine series
- ATCvet code QG Genito-urinary system and sex hormones, a section of the Anatomical Therapeutic Chemical Classification System for veterinary medicinal products
- quod google, an internet-era term meaning "google it", similar to 'qv' (quod vide (q.v.))