Alan James Carter Duncan (born March 31, 1957) is a British politician, and Member of Parliament for Rutland and Melton. Educated at Merchant Taylors School and St John's College, Oxford, he was elected President of the Oxford Union and coxed the college first VIII. He went on to win a Kennedy Scholarship to study at Harvard. After a career as an oil trader, he was elected to Parliament in 1992 as a Conservative, and sits on the front bench as Shadow Secretary of State for International Development.

He is a libertarian, wishing to minimize the state whilst also seeking to abolish laws against drugs. He is on the council of the Conservative Way Forward group. He was the first Conservative MP to openly and voluntarily acknowledge being gay.