The M82 is a recoil-operated, semi-automatic anti-materiel rifle developed by the American Barrett Firearms Manufacturing company. A heavy SASR (Special Application Scoped Rifle), it is used by many units and armies around the world. It is also called the "Light Fifty" for its .50 caliber BMG (12.7 x 99 mm) chambering. The weapon is found in two variants, the original M82A1 (and A3) and the bullpup M82A2. The M82A2 is no longer manufactured, though the XM500 can be seen as its successor.

Barrett Firearms Manufacturing was founded by Ronnie Barrett for the sole purpose of building semi-automatic rifles chambered for the powerful 12.7×99mm NATO (.50 BMG) ammunition, originally developed for and used in M2 Browning machine guns. Barrett began his work in the early 1980s and the first working rifles were available in 1982, hence the designation M82. Barrett designed every single part of the weapon personally and then went on to market the weapon and mass produce it out of his own pocket. He continued to develop his rifle through the 1980s, and developed the improved M82A1 rifle by 1986.