The 23rd Battalion was an infantry battalion of the Australian Army. It was raised in 1915 as part of the Australian Imperial Force for service during World War I and formed part of the 6th Brigade, attached to the 2nd Division. After being formed in Australia, the battalion was sent to Egypt to complete its training, before being committed to the Gallipoli Campaign as reinforcements in September 1915. They remained on the peninsula until the evacuation of Allied troops in December, when they were withdrawn back to Egypt where they were reorganised before being transferred to the Western Front in March 1916. Over the course of the next two-and-a-half years, the 23rd took part in a number of significant battles in France and Belgium, before being disbanded in mid-1919 following the conclusion of hostilities. In 1921, the battalion was re-raised as a part-time unit within the Citizens Forces in the state of Victoria, but was amalgamated with the 21st Battalion in 1929 to form the 23rd/21st Battalion.

The 2/23rd Battalion was an infantry battalion of the Australian Army, which served during the Second World War. Formed in June 1940 from primarily volunteers from Albury, New South Wales, the battalion served in North Africa in 1941–1942 as part of the 26th Brigade, which was assigned to the 7th Division, before being reassigned to the 9th Division. In early 1943, the battalion returned to Australia and later took part in campaigns against the Japanese in New Guinea in 1943–1944 and Borneo in 1945, before being disbanded in 1946.