The XVIII Corps was a British infantry formation during World War I.

It was reactivated, briefly, in Cyprus during World War II as part of a military deception.

British XVIII Corps was formed in France in January 1917 under Lieutenant General Sir Ivor Maxse.

It was dissolved in August 1917 when the South Irish Horse went to be retrained as infantry.

[1] In 1941, during World War 2, the XVII Corps was briefly reactivated as a fictional unit, as part of the Cyprus Defence Plan deception.