ZG or Zg is used to identify:
- Canton of Zug, one of the 26 cantons of Switzerland
- Viva Macau IATA code
- zettagram (written Zg, with capital "Z"), an SI unit of mass (equal to 1021 g)
- zeptogram (written zg, with lower case "z"), an SI unit of mass (equal to 10−21 g)
- Z-G, a collectible action figure game
- Zagreb, the capital and the largest city of Croatia
- ZOEgirl, a pop rock band
- Zerstörergeschwader, a type of unit usually equipped with twin-engined fighters such as the Bf 110 or Me 410