An air gun, also known as an airgun, is a gun that uses compressed air or other gases as a propellant to launch projectiles. Air guns come in both long gun (air rifle) and handgun (air pistol) forms, and they typically propel metallic projectiles that are either diabolo-shaped pellets or spherical shots called BBs. Some air guns may also launch fin-stabilized projectiles such as darts or hollow-shaft arrows. There are three different power sources for modern air guns, depending on the design: spring-piston, pneumatic, or bottled compressed gas (most commonly carbon dioxide) .

Air guns have been used for small game hunting, pest control, recreational shooting, and competitive sports such as the Olympic 10 m Air Rifle and 10 m Air Pistol events. Field Target (FT) is a competitive form of metallic silhouette shooting in which the targets are animal-shaped steel targets with a "kill zone" cut-out, while Hunter Field Target (HFT) is a variation using identical equipment but with differing rules.

It is important to note that while air guns are often used as toys or beginner guns for children, they can pose a serious threat to the pediatric population and their potential for serious injury must be recognized.