The 37mm M3 gun was the first dedicated anti-tank gun fielded by US forces in numbers. Introduced in 1940 it became the standard anti-tank gun of the US infantry with its size enabling it to be pulled by a jeep. However the continuing improvement of German tanks quickly rendered the 37mm ineffective, being unable to penetrate the frontal armour of mid-war tanks, by 1943, it was being gradually replaced in the European and Mediterranean theaters by the more powerful British 57mm M1.
In the Pacific where the Japanese tank threat was less significant the M3 remained in service until the end of the war, but some 57mm guns were issued.
Like many other light anti-tank guns, the M3 was widely used in the infantry support role and as an anti-personnel weapon, firing high-explosive and canister rounds.
Between 1940 and 1943, a total of 18,702 were produced.