The BA-20 was one of the many pre-war armored cars built by the USSR that managed to see action in the early phases of World War II. Physically similar to the FAI armored car, it was based on the chassis of the GAZ-M1 civilian car (itself based on the Ford A and GAZ-A) with modifications for combat use which included bullet- and shrapnel-resistant tires, a modified drivetrain and braking system, an escape hatch on the floor, and new engine. However, it lacked adequate off-road performance and protection and defensive armament was generally considered to be poor, which consisted of a 7.62-mm DT machine gun fitted in a vertical-sided (later conical) turret. Despite this, the BA-20 was produced in large numbers where it equipped HQ staffs, reconnaissance, and communications units. It was first used in combat by the Spanish Republican side during the Spanish Civil War, and later with the Red Army during the Khalkin Gol incident, the 1939 invasion of Poland, and the Winter War against Finland. It was still under production when the Germans invaded in 1941 and was used during the early stages of the conflict but was gradually phased out once the BA-64 was available in large numbers.

The BA-20 began production in 1935 entering service sometime that year or the next. The BA-20M was an improved version, with command vehicles featuring a whip antenna in place of the earlier clothes-rail antenna. The BA-20ZhD was modified for use on rails. Captured vehicles were given the German designation Panzerspähwagen BA-202(r)