Sir Andrew Rae Duncan (3 June 1884 – 30 March 1952) was a British businessman who was brought into government during World War II, serving twice as both President of the Board of Trade and Minister of Supply.
Duncan was a Director of the Bank of England and of Imperial Chemical Industries. He was chairman of the Central Electricity Board from 1927 to 1935, and chairman of the British Iron and Steel Federation from 1935 until 1945. He was elected as a "National" Member of Parliament (MP) for the City of London in a 1940 by-election and was made a member of the Cabinet and a Privy Counsellor. He was re-elected at the 1945 election, and stepped down at the 1950 general election.
In addition to his service in the United Kingdom, Duncan was appointed in 1926 by Canadian Prime Minister William Lyon Mackenzie King in response to the Maritime Rights Movement to chair the Royal Commission on Maritime Claims, which was thus nicknamed the "Duncan Commission".
In 1916, he married Anne Jordan. They had two sons, one of whom was killed in action in 1940. He died in his sleep on 30 March 1952, aged 67.