John Waldegrave (Royal Navy officer)

Commander John Montagu Granville Waldegrave, DSC (29 August 1905 – 18 February 1944) was a British naval commander during World War II.

Waldegrave was the eldest son of the 5th Baron Radstock. He commanded the cruiser HMS Vindictive (1918) 1938–1939, and the sloop HMS Puffin (L52) in 1939. He was awarded the DSC for anti-submarine work performed while commanding the Puffin.

On 29 June 1940, he married Lady Hersey Boyle, the second daughter of the retired navy man, the 8th Earl of Glasgow, and they had two daughters:
 * Hon. Horatia Marion Waldegrave (b. 1 August 1941), married Oliver John Diggle (b. 19 February 1934) and had three children Rowena Mary Diggle, John Wyndham Hugh Diggle and Emma Georgiana Diggle
 * Hon. Griselda Hyacinthe Waldegrave (b. 6 June 1943), married and had issue

From 1942–1943, he served in the Operations Division, attached to shore station HMS President (1918). On 6 September 1943, he was assigned to the cruiser HMS Penelope (97) as executive officer. On 18 February 1944, Penelope was torpedoed by GS U-410 while returning from Anzio and Cmdr. Waldegrave was lost with the ship.