GZ or gz may refer to:
- .gz, the file extension for gzip files
- 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
- Gestrichener Zellstoffkarton, 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
- Air Rarotonga
- Metal Gear Solid V: Ground Zeroes, a 2014 video game
