Admiral the Hon. Sir Reginald Aylmer Ranfurly Plunkett-Ernle-Erle-Drax, KCB, DSO, JP, DL (28 August 1880 – 16 October 1967) was a British admiral. He is often referred to as Reginald Plunkett or Reginald Drax. He was the younger son of the 17th Baron of Dunsany (1853–1899) and his wife, the former Ernle Elizabeth Louisa Maria Grosvenor Ernle-Erle-Drax (1855–1916), née Burton. His elder brother was Lord Dunsany, a prolific writer and author of over 60 books.