The Australian and New Zealand Army Corps (ANZAC) was originally a First World War army corps of the Mediterranean Expeditionary Force. It was formed in Egypt in December 1914, and operated during the Gallipoli campaign. General William Birdwood commanded the corps, which primarily consisted of troops from the First Australian Imperial Force and 1st New Zealand Expeditionary Force, although there were also British and Indian units attached at times throughout the campaign. The corps disbanded in 1916, following the Allied evacuation of the Gallipoli peninsula and the formation of I ANZAC Corps and II ANZAC Corps. The corps was reestablished, briefly, in the Second World War during the Battle of Greece in 1941. The term 'ANZAC' has been used since for joint Australian–New Zealand units of different sizes. The day ANZAC day is used for the rememberence from the ANZACS who have died.

Corps is a term used for several different kinds of organization. A military innovation by Napoleon I, the formation was first named as such in 1805. The size of a corps varies greatly, but two to five divisions and anywhere from 40,000 to 80,000 are the numbers stated by the US Department of Defense.