Sir Arthur Antony Duff GCMG CVO DSO DSC PC (25 February 1920 – 13 August 2000) was a senior British diplomat and Director General of MI5.

[1] He was Counsellor and Head of the Chancery of the United Kingdom Embassy in West Germany from 1962 to 1964, the British Ambassador to Nepal from 1964 to 1965; the Head of the South Asia Department of the Foreign Office from 1965 to 1969; the Deputy High Commissioner to Malaysia from 1969 to 1972; and the British High Commissioner to Kenya from 1972 to 1975.

[1] Having led the British official delegation to the Lancaster House talks, he became Deputy Governor of Southern Rhodesia under Lord Soames from 1979 to 1980.

[5] Duff was sworn of the Privy Council in 1980, the first diplomat to be so honoured since Sir Alexander Cadogan in 1940.

[8] In 1944, Duff married Pauline Sword (née Bevan), a widow who had a child from her first marriage.