Henry Wallace Stuart Clark MBE (20 November 1926 – 8 May 2011) was a sailor, author and businessman from Northern Ireland. Clark was educated at Shrewsbury School and served in the Royal Navy Volunteer Reserve in World War II. He was an officer in the Ulster Special Constabulary and upon its dissolution became a major in the Ulster Defence Regiment serving until 1981. He was the elder brother of Henry Maitland Clark, MP for North Antrim from 1959 to 1970. He was appointed High Sheriff of County Londonderry for 1969.