Sir Pierson John Dixon GCMG, CB (13 November 1904 – 22 April 1965) was an English diplomat.
Bob Dixon was the son of Pierson John Dixon and he was educated at Bedford School and Pembroke College, Cambridge. He was the Principal Private Secretary to the Foreign Secretary between 1943 and 1948. He held the post of Ambassador to Czechoslovakia (1948–1950) and he was invested as Knight Commander of the Order of St. Michael and St. George in 1950. He later held the offices of Deputy Under-Secretary of State, Foreign Office (1950–1954) and Permanent Representative of the United Kingdom to the United Nations (1954–1960). He was involved during the Suez Crisis in 1956. He was invested as a Knight Grand Cross, Order of St. Michael and St. George in 1957 and also served as the Ambassador to France between 1960 and 1964.
He married Alexandra Atchley in 1928 and they had a son and two daughters. Their son Piers Dixon is an English Conservative politician who represented Truro between 1970 and 1974.