Denys Gravenor Rhodes (9 July 1919 – 30 October 1981) was an English writer. He was best known for his novel The Syndicate which was adapted into a 1968 film. He was married twice, once to actress Rachel Gurney (from 1946 to 1950) and secondly (in 1950) to The Honourable Margaret Elphinstone (1925-2016), a first cousin of Elizabeth II.
Rhodes was born in Ireland, the son of (Arthur) Tahu Gravenor Rhodes, MVO (d. 1947), a solicitor and Captain in the Grenadier Guards, by his wife Hon. Helen Cecil Olive, eldest daughter of the 5th Lord Plunket, Governor of New Zealand from 1904 to 1910. His paternal grandfather was the New Zealand politician Arthur Edgar Gravenor Rhodes OBE and his great uncle was the politician and pastoralist William Barnard Rhodes.
Rhodes served in the Second World War with the Rifle Brigade, fighting in North Africa and Italy. After his second marriage he lived and wrote at Uplowman House at Uplowman in Devon, until inoperable lung cancer led to a move nearer London. They were offered The Garden House in Windsor Great Park by the Queen, where his wife continued to live until her own death in 2016, and where she wrote her 2011 memoir The Final Curtsey.
They had four children: two sons, Simon and Michael, and two daughters, Annabel and Victoria; their elder daughter Annabel served as a bridesmaid to Princess Margaret in 1960.