The 2/5th Battalion was an infantry battalion of the Australian Army that operated during World War II. It was raised at Melbourne, Victoria, on 18 October 1939 as part of the Second Australian Imperial Force, attached to the 17th Brigade of the 6th Division. The 2/5th was one of only two Australian infantry battalions to fight against all of the major Axis powers during the war, seeing action against the Germans and Italians in Egypt, Libya, Greece and Crete, and the Vichy French in Syria, before returning to Australia in 1942 to fight the Japanese following a period of garrison duties in Ceylon, where it formed part of an Australian force established to defend against a possible Japanese invasion.

The 17th Brigade was an infantry brigade in the Australian Army. First raised in 1912 as a Militia formation to provide training under the compulsory training scheme, the brigade was later re-raised as part of the First Australian Imperial Force during World War I. Established in 1917 in the United Kingdom, it was broken up and disbanded without seeing action, and its personnel used as reinforcements for other formations. Reformed during World War II, it took part in fighting in Libya, Greece, Crete, Syria in 1941–1942. Following Japan's entry into the war, the Australian government pressed for the 6th Division's return, and the 17th Brigade was subsequently brought back from the Middle East, via Ceylon where they undertook defensive duties until July 1942. Following the brigade's return to Australia, it was deployed to New Guinea for two campaigns: the Salamaua–Lae campaign in 1943 and the Aitape–Wewak campaign in 1944–1945. After the war, the brigade was disbanded in January 1946. Today, its name is perpetuated by the 17th Sustainment Brigade, which was raised as a logistics formation in May 2006.