An attack helicopter is an armed helicopter with the primary role of an attack aircraft, with the offensive capability of engaging ground targets such as enemy infantry, military vehicles and fortifications. Due to their heavy armament they are sometimes called helicopter gunships.

Attack helicopters can use weapons including autocannons, machine guns, rockets, and anti-tank missiles such as the AGM-114 Hellfire. Some attack helicopters are also capable of carrying air-to-air missiles, though mostly for purposes of self-defense against other helicopters and low-flying light combat aircraft.

A modern attack helicopter has two primary roles: first, to provide direct and accurate close air support for ground troops; and second, the anti-tank role to destroy grouped enemy armor. Attack helicopters are also used as protective escort for transport helicopters, or to supplement lighter helicopters in the armed reconnaissance roles. In combat, an attack helicopter is projected to destroy targets worth around 17 times its own production cost before being destroyed.