Colonel Windham Henry Wyndham-Quin, 5th Earl of Dunraven and Mount-Earl CB DSO (7 February 1857 – 23 October 1952) was an Irish peer, British Army officer and a Conservative Member of Parliament for South Glamorganshire (1895–1906).

He succeeded to the Earldom on the death of his cousin Windham Wyndham-Quin, 4th Earl of Dunraven and Mount-Earl, who died in 1926 without male issue.

[1] He again volunteered for service in South Africa in early 1900, during the Second Boer War, and was appointed a captain in the Imperial Yeomanry on 14 February 1900.

He was mentioned in despatches, received the Queen's medal (3 clasps), and was awarded the Distinguished Service Order (DSO) in November 1900.

[4] On return from South Africa he raised and commanded the Glamorgan Imperial Yeomanry, a full regiment that perpetuated 4th Company.