Major-General Guy Payan Dawnay, CB, CMG, DSO, MVO (23 March 1878 – 19 January 1952) was a British Army officer and merchant banker.

He served in South Africa during the Second Boer War, where he was a staff officer as Aide-de-camp to Major-General Bruce Hamilton, in command in Eastern Transvaal.

Following the end of hostilities, he left Cape Town with Hamilton on board the SS Walmer Castle in late June 1902,[2] and arrived at Southampton the following month.

[4] Following the withdrawal from Gallipoli he was shifted to the headquarters of the newly formed Egyptian Expeditionary Force.

[6] In 1909 whilst a student at the Staff College, Camberley, he co-founded the Chatham Dining Club with Rupert Ommanney.