William A. Seiter (June 10, 1890 – July 26, 1964) was an American film director.
Seiter was born in New York City. After attending Hudson River Military Academy, Seiter broke into films in 1915 as a bit player at Mack Sennett's Keystone Studios, doubling a cowboy. He graduated to director in 1918.
At Universal Studios in the mid-1920s, Seiter was principal director of the popular Reginald Denny vehicles, most of which co-starred Seiter's then wife Laura La Plante (his second wife was actress Marian Nixon). This period also included The Beautiful and Damned and The Family Secret.
In the early talkie era, Seiter helped nurture the talents of RKO's comedy duo Wheeler & Woolsey in such rollicking features as Caught Plastered (1931) and Diplomaniacs (1933). He also directed the Laurel and Hardy feature Sons of the Desert (1933), their only film together. Other films include Sunny, Going Wild, Kiss Me Again, Hot Saturday, Way Back Home, Girl Crazy, Rafter Romance, Roberta, Room Service, Susannah of the Mounties, Allegheny Uprising, You Were Never Lovelier, Up in Central Park, One Touch of Venus.