GZ or gz may refer to:

  • .gz, the file extension for gzip files (GNU zip, an open source file compression program)
  • GZ, an HCPCS Level II modifier meaning an item or service is expected to be denied as not reasonable or necessary
  • GZ, the "righting moment" or "righting arm" acting to restore a tilting ship to vertical; see metacentric height
  • Galaxy Zoo, a crowdsourced astronomy project
  • Gaza Strip (FIPS PUB 10-4 territory code)
  • Gestrichener Zellstoffkarton (German; DIN 19303 Code), a grade of paperboard also known as solid bleached board
  • Ground Zero, in military parlance
  • Guangzhou, capital and largest city of Guangdong Province in southeastern China
  • Guizhou, a province of China (Guobiao abbreviation GZ)
  • Air Rarotonga (IATA airline designator)
  • Metal Gear Solid V: Ground Zeroes, a 2014 video game