For the American film and television actor, see William Tannen (actor).

William Tannen (born August 31, 1942 in New York City) is an American film producer and director. He graduated Boston University and returned to his hometown of New York City to pursue a career in advertising. He worked for D'Arcy, BBD&O and Young & Rubicam Advertising Agencies. He started Sunday Productions in order to produce and direct television commercials. He directed his first film, the short subject Eulogy for R.F.K., which opened at the New York Film Festival with The Battle of Algiers. Besides working in Los Angeles and New York, Tannen has directed films in Africa, Czech Republic, Europe, New Zealand, Australia, Canada, Mexico, and South America. In 2004, he moved to Portland, Oregon.