Sir Roger William Houssemayne Du Boulay KCVO CMG (born 20 March 1922) is a retired British diplomat who served as Vice-Marshal of the Diplomatic Corps.
Du Boulay was educated at Winchester College and the University of Oxford. On 6 November 1942 he was commissioned into the Royal Air Force Volunteer Reserve, and saw active service in the Second World War. On 28 February 1947 he was promoted to Flight Officer. He relinquished his commission on 28 February 1957.
After the war Du Boulay joined the Colonial Service, and served in Nigeria between 1949 and 1958. In 1959 he joined Her Majesty's Diplomatic Service, and held appointments in Washington, the Foreign Office, Manilla and Paris. From 1973 to 1975 he was Resident Commissioner of the New Hebrides. He was made a Companion of the Order of St Michael and St George in the 1975 Birthday Honours. On 12 December 1975 he became Vice-Marshal of the Diplomatic Corps, retaining the post until 9 April 1982. He was knighted in the Royal Victorian Order in 1982, having been made a CVO in 1972. He later served as an adviser to the Solomon Islands and Swaziland governments.