The 57th Battalion was an infantry battalion of the Australian Army. Formed in early 1916 for service during World War I, the battalion served on the Western Front until the end of the war, when it was disbanded. In 1921, it was re-raised as a part-time unit in Victoria, known as "The Merri Regiment". In 1930, the battalion was amalgamated with the 60th Battalion, to form the 57th/60th Battalion, which remained linked until it was disbanded in 1946, after having fought against the Japanese in New Guinea and Bougainville during World War II.