The 37mm M3 anti-tank gun was introduced in 1940 in United State Army. Nevertheless, its service life was short, and soon became in an obsolete weapon. The continuing improvement of German tanks quickly rendered the 37 mm ineffective. They had to be replaced in all European Fronts. On the other and, in the Pacific Front, because Japanese tanks were lighter than their European alied's tanks, its service life was longer, and it remained in service until the end of the war. In fact, the M3 anti-tank gun was very effective against Japanese armour. 

During its service life, 37mm M3 anti-tank gun was the standard anti-tank gun of the U.S. infantry. Its size, the weapon weighed less than 1,000 lbs., enabled it to be pulled easily. Usually, a jeep was used for transport of this light weapon. In general, the M3 proved to be an accurate direct fire weapon for stationary hard targets. Anti-tank ammunition was developed with a projectile velocity of 2900 fps. This gun could fire 5-20 rounds per minute either fixed HE, AP, APC and canister projectiles.

Based on German 37 mm PaK 35/36, its development was consequence of the success of the German anti-tank gun in Spanish Civil War, previous to World War II. US Army acquired two PaK 36 guns for study. This 37mm calibre development became to be very popular among Armies around the world in 30s. It used a fully manual vertically-sliding breechblock (as opposed to the German semiauto breech). M3 utilized fixed ammunition. Projectiles were fitted with a 37x223R cartridge case, designated Cartridge Case M16. Available projectiles included armor-piercing, high-explosive and canister.), which were able to penetrate 1-2 inches of armor at 500 yards, depending on the type of shell used and the angle of the armor.

The M3 was integrated mainly in US Infantry Divisions, nevertheless it was used by the 10th Mountain Division too, the only mountain division formed in the U.S. One US Armoured Division was also equipped with M3 when it was created, entering into combat in North Africa. US Marine Corps used 37mm M3 anti-tank gun widely until the end of the war.

The M3 saw action for the first time during the defence of the Philippines in December 1941. Later in Guadalcanal Campaign, Battle of Tarawa, etc. In Europe, the M3 saw action in North African Campaign, included Battle of Kasserine. Sicily landing, in the early stages of Italian Campaign, was the last important battle where M3 was used as main anti-tank gun in US Army. 

Between 1939 and 1943 over 20,000 37 mm anti-tank guns were manufactured by Watervliet Arsenal. The carriage was manufactured by Rock Island Arsenal. They were developed four test variants (T3, T7, T8, T10), three model variants (M3, M5, M6) and four carriage variants (T1, T1E1, T5, M4A1).