The 2/16th Battalion was an infantry battalion of the Australian Army, serving during World War II. Attached to the 21st Brigade that was assigned to the 7th Division, the 2/16th was raised in 1940 as part of the Second Australian Imperial Force from volunteers drawn mainly from the state of Western Australia. After training in Australia, the battalion was deployed to the Middle East where it undertook defensive duties along the Egyptian–Libyan border in early 1941 before taking part in the Syria–Lebanon campaign, fighting against Vichy French forces in June and July. At the conclusion of the campaign, the 2/16th remained in Lebanon, contributing to the Allied occupation force there, before returning to Australia in early 1942 following Japan's entry into the war. In August 1942, they were committed to the fighting along the Kokoda Track and then later fought around Buna and Gona. After a period of rest and reorganisation in Australia, the battalion fought around Lae and then took part in the Finisterre Range campaign in 1943–44. Its final campaign of the war came in Borneo in July 1945. At the end of the war, the 2/16th were disbanded in January 1946.

The 21st Brigade was a brigade-sized infantry unit of the Australian Army. It was briefly raised in 1912 as a Militia formation providing training as part of the compulsory training scheme. Later, it was re-formed in April 1940 as part of the Second Australian Imperial Force, the unit was raised for service during World War II. As part of the 7th Division the brigade's constituent units were raised from volunteers from several Australian states. After rudimentary training in Australia, the brigade deployed for the Middle East in October 1940. Defensive duties were mounted along the Libyan border in early 1941, before the brigade was committed to the Syria-Lebanon campaign, fighting against Vichy French forces. In early 1942, following Japan's entry into the war, the brigade returned to Australia. After a period of defensive duties in Australia, it was deployed to New Guinea and subsequently played a key role in the Kokoda Track campaign, delaying the Japanese advance towards Port Moresby and then joining the pursuit as the Japanese withdrew towards Buna–Gona. In 1943–1944, the brigade took part in the capture of Lae and the Ramu Valley–Finisterre Range campaign. Its final campaign of the war, came in the final months when it took part in the Balikpapan landings. It was disbanded in 1946.