The Girandoni air rifle is an air gun designed by Italian inventor Bartolomeo Girandoni circa 1779. The weapon was also known as the Windbüchse. One of the rifle's more famous associations is its use on the Lewis and Clark Expedition to explore and map the Louisiana Purchase of 1803.

An air gun or airgun is a gun that uses energy from compressed air or other gases that are mechanically pressurized and then released to propel and accelerate projectiles, similar to the principle of the primitive blowgun. This is in contrast to a firearm, which shoots projectiles using energy generated via exothermic combustion (deflagration) of chemical propellants, most often black powder or smokeless powder.