CAG may refer to:
- CAG, in biology is the codon that codes for the amino acid glutamine
- The CAG promoter used in molecular biology
- Comptroller and Auditor General
- Commander, Air Group, the informal name for the senior US Navy officer who, as leader of the Carrier air wing, is responsible for air operations aboard an aircraft carrier
- Cheap Ass Gamer, an online bbs community
- Citrix Access Gateway
- Closed angle glaucoma
- Consumer Action Group
- Combat Applications Group, an abbreviation of the official name of Delta Force, a United States Army Special Operations Command military unit
- Commentaria in Aristotelem Graeca, a series of original-language texts of ancient and Byzantine commentaries on Aristotle
- Computer-assisted gaming, used for example for PnP role-playing games
- Consensus audit guidelines, a set of twenty security controls for cyber defense published by the SANS Institute
- Chassis Air Guide, in computers is Intel's thermal solution to PC chassis
- Cagliari-Elmas Airport (IATA airport code: CAG) in Cagliari, Sardinia, Italy
- Craig-Moffat Airport (FAA airport code: CAG) in Craig, Colorado, United States
- CAG is the ICAO airline designator for China National Aviation Corporation (CNAC)
- Communication Arts Guild