Sir Denis William Boyd (6 March 1891 – 21 January 1965) was a Royal Navy officer who served as Fifth Sea Lord from 1943 to 1945, and as Commander-in-Chief, Far East Fleet from 1946 to 1949.

He was briefly Commanding Officer of the destroyer HMS Valentine in 1932,[1] before joining the Tactical Division of the naval Staff in 1933 and becoming its Director in 1934.

[1] Boyd became Commanding Officer of HMS Hardy and Captain (D) of the 2nd Destroyer Flotilla at Malta in 1936; a post that included responsibility for patrols off Spain during the Spanish Civil War.

[2] He was then made commanding officer of the Torpedo School HMS Vernon in 1938, serving there until the outbreak of World War II.

[1] He was appointed Fifth Sea Lord and Chief of Naval Air Equipment in 1943, and was promoted to vice admiral in August 1944.