William Duer was an American lawyer and politician. In addition to serving in local offices in both California and New York, he represented New York in the United States House of Representatives from 1847 to 1851.

William Duer was a British-born American jurist, developer, and financial speculator from New York City. A Federalist, Duer wrote in support of ratifying the United States Constitution as "Philo-Publius". He had earlier served in the Continental Congress and the convention that framed the New York Constitution. In 1778, Duer signed the United States Articles of Confederation and is one of the Founding Fathers of the United States.