An air gun or airgun (also called pellet gun) is any one of a variety of guns that propel projectiles by means of compressed air or other gas, in contrast to firearms which use a propellant charge. Both the rifle and pistol forms (air rifle and air pistol) normally fire metallic projectiles, either pellets or spherical balls based on the BB size of birdshot – although a few fire darts.

Air guns that only use plastic projectiles are classified as airsoft guns.

The earliest airguns were more effective compared to contemporary early firearms for many hunting and military uses, but as firearms improved the airgun became largely relegated to sport target shooting and plinking. Neither of these uses required much power, and so airguns came to be seen as a safe, less threatening alternative to firearms, and typically treated differently by legal systems.

In recent times there has been an upsurge of interest again in more powerful airguns.

Currently, we have three subcatagories of air guns.