STG can be an abbreviation for:
- Pound sterling, currency of the United Kingdom
- St. George Airport (Alaska), IATA code
- Security Threat Group, prison gang
- Shiny Toy Guns, American rock band
- Shoot 'em up computer games, ShooTing Game
- Sigma Tau Gamma, U.S. all-male college social fraternity
- Slaves to Gravity, U.K band
- Somali Telecom Group, Somalia telecommunications company
- Sonar Technician, United States Navy rating
- Special Tactics Group, New Zealand Police counter-terrorism group
- Star Trek Generations, 1994 science fiction film
- Stirling railway station, Scotland, station code
- Sturmgewehr, German assault rifle
- Superior temporal gyrus, bump or ridge on the surface of the brain
- Stomatogastric ganglion, a bundle of 26 nerve cell bodies in the crustacean nervous system
- Steam Turbine generator