The II Corps was an army corps of the British Army formed in both the First World War and the Second World War. There had also been a short-lived II Corps during the Waterloo Campaign.

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.