Dayton Duncan (born September 3, 1949) is an American screenwriter, producer and former political aide.

Born and raised in Indianola, Iowa, Duncan graduated from the University of Pennsylvania in 1971 with a degree in German literature and was also a fellow at Harvard's Shorenstein Center for Press, Politics and Public Policy.

Duncan served as chief of staff to New Hampshire governor Hugh Gallen until the latter's death in 1982.

Dayton wrote and co-produced the Ken Burns-directed documentaries Lewis & Clark: The Journey of the Corps of Discovery, Mark Twain, Horatio's Drive: America's First Road Trip, Country Music and The National Parks: America's Best Idea.

Dayton co-wrote Stephen Ives's Erik Barnouw Award-winning documentary series The West.