The M1 carbine (formally the United States Carbine, Caliber .30, M1) is a lightweight[7] semi-automatic carbine that was a standard firearm for the U.S. military during World War II, the Korean War and the Vietnam War. The M1 carbine was produced in several variants and was widely used by paramilitary and police forces around the world, and also became a popular civilian firearm after World War II.

The M2 carbine is the selective-fire version of the M1 carbine, capable of firing in both semi-automatic and full-automatic. The M3 carbine was an M2 carbine with an active infrared scope system.[8]

Despite having a similar name and physical outward appearance, the M1 carbine is not a carbine version of the M1 Garand rifle. On July 1, 1925, the U.S. Army began using the current naming convention where the "M" is the designation for "Model" and the number represents the sequential development of equipment and weapons.[9] Therefore, the "M1 carbine" was the first carbine developed under this system. The "M2 carbine" was the second carbine developed under the system, etc.