The 37 mm gun M1 was an anti-aircraft autocannon developed in the United States.

In early World War II, each Army Anti-Aircraft Artillery (AAA) Auto-Weapons battalion was authorized a total of thirty-two 37 mm guns in its four firing batteries, plus other weapons.

The system was powered by the M5 generating unit.

[citation needed] The M1 utilized fixed ammunition.

Projectiles were fitted with a 37×223mmSR cartridge case.