Kenneth Welsh, CM (March 30, 1942 – May 5, 2022) was a Canadian film and television actor (sometimes credited as Ken Welsh). He was known to Twin Peaks fans as the multifaceted villain Windom Earle, and later played the father of Katharine Hepburn (Cate Blanchett) in Martin Scorsese's film The Aviator.

In 1984 he was nominated for a Genie Award for Best Actor for the role of Reno Colt in the film Reno and the Doc, written and directed by Charles Dennis. In 1997 Welsh staged Dennis's play SoHo Duo at the West Bank Theatre in New York.

Welsh was born in Edmonton, Alberta, to a father who worked for Canadian National Railway. He grew up in Alberta and studied drama in school. He later moved to Montreal and enrolled in the National Theatre School. After graduating, he auditioned for the Stratford Festival in Ontario and then spent the first seven years of his career on stage.

Welsh portrayed historical figures including Thomas E. Dewey, Colin Thatcher, Harry S. Truman (twice), Thomas Edison, James "Scotty" Reston, General Harry Crerar, and James Baker.