The Wilby Conspiracy is a 1975 British adventure thriller film directed by Ralph Nelson and starring Michael Caine, Sidney Poitier, and Nicol Williamson. Filmed in Kenya, it was written by Rodney Amateau, based on the 1972 novel by Peter Driscoll. It had a limited release in the US.

Thomas Nicol Williamson was a British actor. He was once described by playwright John Osborne as "the greatest actor since Marlon Brando". He was also described by Samuel Beckett as "touched by genius" and viewed by many critics as "the Hamlet of his generation" during the late 1960s.