Sir John Oscar Moreton (28 December 1917 – 14 October 2012) was a British diplomat.
Moreton born in Oakham, Rutland, and was educated at St Edward's School, Oxford and Trinity College, Oxford. He served in the Royal Artillery during the Second World War, and was awarded the Military Cross in 1944, following the Battle of Kohima.
Moreton joined the Diplomatic Service in 1946. After postings to Kenya (1953–55) and Nigeria (1961–64), he served as Ambassador of the United Kingdom to Vietnam from 1969 to 1971. He was then the High Commissioner to Malta from 1972 to 1974, and between 1975 and 1977, served in the United States, first as Deputy Permanent Representative in the UK Mission to the United Nations in New York, and then as Minister in Washington, the deputy to the Ambassador.
- "Announcements: Moreton". The Daily Telegraph. 22 October 2012. Retrieved 22 October 2012.
- "Sir John Moreton". The Daily Telegraph. London: TMG. 12 December 2012. Retrieved 9 March 2016.
- Keleny, Anne (31 October 2012). "John Moreton: War hero who, as a postwar diplomat, helped to dismantle the British empire". The Independent. London: INM. Retrieved 9 March 2016.
- "Moreton, Sir John (Oscar)". Who's Who 2008. A & C Black. 2008. Retrieved 11 October 2008.
| British Ambassador to Vietnam
Sir Anthony Abell
| Gentleman Usher of the Blue Rod
Sir John Margetson