The 2/1st Machine Gun Battalion was a battalion of the Australian Army that was raised for service during World War II as part of the 6th Division. When it was formed on 14 December 1939, its component companies were spread across several Australian states, but it was later concentrated at Ingleburn, New South Wales, where it completed basic training in the early months of the war. In mid-1940, the battalion embarked for overseas, bound initially for the Middle East, but following the Fall of France it was diverted to the United Kingdom. Along with a larger contingent of Australians, it helped to bolster the island's garrison, undertaking defensive duties during a period when it was expected that the Germans might launch a cross-Channel invasion.