U.S. 12th Army Group

Twelfth United States Army Group
Twelfth Army Group Shoulder Sleeve Insignia
Active	1944–45
Country	United States
Branch	United States Army
Type	Army group
Role	Army Group Headquarters
Size	1.3 million men
Part of	Allied Expeditionary Force
Engagements	World War II
Commanders
Notable commanders	Omar Bradley

The Twelfth United States Army Group was the largest and most powerful United States Army formation ever to take to the field. It controlled the majority of American forces on the Western Front in 1944 and 1945. It was commanded by General Omar Bradley with its headquarters established in London on 14 July 1944.

Bradley's First United States Army, which later formed part of the Twelfth Army Group, formed the right wing of the Allied lines during the Normandy landings and the Battle of Normandy. They were joined during July by the Third United States Army, under the command of General George S. Patton. Until September, when General Eisenhower assumed overall command of the Allied land forces in Northwest Europe, the U.S. forces in Normandy were included with the British Second Army and the First Canadian Army in the British headquarters formation 21st Army Group, commanded by General Montgomery.

After the breakout from the beach-head at Normandy, the Twelfth Army Group formed the center of the Allied forces on the Western Front. To the north was the British 21st Army Group (the 2 aforementioned field armies) and, to the south, advancing from their landing on the Mediterranean coast, was the Sixth United States Army Group (Seventh United States Army and French First Army).