For other men with this name, see the disambiguation page: William Duer.

William Duer (March 18, 1747 – May 7, 1799) was an American lawyer, developer, and speculator from New York City. He represented New York in the Continental Congress in 1788 and 1789.

His son William Alexander Duer was a justice of the New York State Supreme Court, and for many years the President of Columbia University. His Grandson William Duer served in the U.S. Congress.