Commander Alexander George Francis Drogo Montagu, 10th Duke of Manchester, OBE, RN (2 October 1902[1] – 23 November 1977) was a Royal Navy officer and British hereditary peer.

Born at Tandragee Castle in County Armagh, Ulster, in the north of Ireland on 2 October 1902, Lord Mandeville was the son of the 9th Duke of Manchester by his marriage to Helena Zimmerman, the only child of Eugene Zimmerman, of Cincinnati, Ohio, a railway president and major stockholder in Standard Oil.

[6] On 5 May 1927 he married firstly, at Kimbolton Castle, Huntingdonshire, Nell Vere Stead (Ashfield, Sydney, Cumberland County, New South Wales, Australia, 1902 – 2 September 1966), daughter of Sydney Vere Stead (1861 – South Yarra, Melbourne, County of Bourke, Victoria, Australia, 1929), of Melbourne, and wife Jessie Lillian Dickinson (Newtown, Sydney, Cumberland County, New South Wales, Australia, 1873 – Armadale, Melbourne, County of Bourke, Victoria, Australia, 1926), by whom he had two sons: On 7 February 1969 he married secondly, and without further issue, Elizabeth (née Fullerton) Coleman Crocker (1913–2007), daughter of Samuel Clyde Fullerton of Miami, Oklahoma.

[8] At the time of his death in 1977 he was still listed in Who's Who as living at Kapsirowa, Hoey's Bridge, Kenya,[5] but he died in London, after running through most of his inherited wealth.

[6] His elder son, Sidney Arthur Robin George Drogo Montagu, succeeded him to the family titles.