Alan James Carter Duncan (born 31 March 1957) is a British politician. He is the Conservative Member of Parliament for Rutland and Melton and Shadow Leader of the House of Commons.
Duncan began his career in the oil industry with Royal Dutch Shell, and was first elected to the House of Commons in the 1992 general election. After several minor positions in the government of John Major, he played a key role in William Hague's successful bid for the Conservative leadership in 1997. He received several promotions to the Conservative front bench until he eventually joined the Shadow Cabinet after the 2005 general election and stood for the Conservative leadership in 2005 but withdrew early on due to a lack of support. Eventual winner David Cameron appointed him Shadow Secretary of State for Trade and Industry in December 2005, the title of which was changed to its current form in July 2007.
He is known as one of the most strident and ideological libertarians within the leading ranks of the Conservative Party, and is a leading member of the Thatcherite Conservative Way Forward grouping. He is also well known as the first openly gay Conservative Member of Parliament, having publicly come out in 2002.