The 6th Division was an infantry division of the Australian Army. It was raised briefly in 1917 during World War I, but was broken up to provide reinforcements before seeing action. It was not re-raised until the outbreak of World War II, when it was formed as a unit of the Second Australian Imperial Force. Throughout 1940–41 it served in the North African Campaign, the Greek campaign, on Crete and in Syria, fighting against the Germans, Italians and Vichy French. In 1942, the division left the Middle East and returned to Australia to meet the threat of Japan's entry into the war. Part of the division garrisoned Ceylon for a short period of time, before the division was committed to the New Guinea campaign. In New Guinea, its component brigades had a major role in the successful counter-offensive along the Kokoda Track, at Buna–Gona and around Salamaua–Lae in 1942–43. Throughout late 1943–44, the division was re-organised in Australia before being committed as a complete formation to one of the last Australian operations of the war around Aitape–Wewak in 1944–45.

A division is a large military unit or formation, usually consisting of between 10,000 and 25,000 soldiers. In most armies, a division is composed of several regiments or brigades; in turn, several divisions typically make up a corps.