Commander The Honourable John Montagu Granville Waldegrave, DSC RN (29 August 1905 – 18 February 1944) was a British naval commander during World War II.
Waldegrave was the only son of the Montague Waldegrave, 5th Baron Radstock and his wife, Constance Marion Brodie.
Waldegrave commanded the cruiser 1938–1939, and the sloop in 1939. He was awarded the DSC for anti-submarine work performed while commanding the Puffin.
From 1942 to 1943, he served in the Operations Division, attached to shore station . On 6 September 1943, he was assigned to the cruiser as executive officer. On 18 February 1944, Penelope was torpedoed by while returning from Anzio and Cmdr. Waldegrave was lost with the ship.
On 29 June 1940, Waldegrave married Lady Hersey Boyle (11 July 1914 – 7 February 1993), second daughter of retired navy man Patrick Boyle, 8th Earl of Glasgow. They had two daughters:[1]