M1A1, M1-A1, M1 A1, or M-1A1 may refer to:
Military M1A1 Abrams, a variant of the M1 Abrams battle tank M1A1 carbine, a variant of the M1 carbine with a folding stock for paratroopers M1A1 Flamethrower, an anti-personnel weapon M1A1 bazooka, a variant of the bazooka rocket launcher Thompson M1A1, a variant of the Thompson submachine gun M1A1, an anti-aircraft 90 mm gun M1A1, a U.S. Army bangalore torpedo used in World War II M1A1, a variant of the M1 75mm pack howitzer (later renamed M116)
Other uses M1A1, a port of the computer game Marathon "M1 A1", a song on the album Gorillaz by Gorillaz
See also M1 to A1(M), an extension of the M1 motorway in Yorkshire, England