The Browning Automatic Rifle (more formally designated first as the Rifle, Caliber .30, Automatic, Browning, M1918 and later the Browning Automatic Rifle, Caliber .30, M1918A2; and commonly known as the BAR), is a family of automatic rifles (or machine rifles) and light machine guns used by the United States and other countries during the 20th century.

It was designed in 1917 by the weapons designer John Browning, primarily as a replacement for (and improvement on) the French-made Chauchat and Hotchkiss M1909. The BAR was originally intended as a light automatic rifle, but spent much of its career in various guises used in the light machine gun role with a bipod. The original M1918 version was and remains the lightest service machine gun to fire the .30-06 Springfield cartridge, though the limited capacity of its standard 20-round magazine tended to hamper its utility as a light machine gun.