The Horse in the Gray Flannel Suit is a 1968 American comedy film directed by Norman Tokar, with a screenplay by Louis Pelletier, and starring Dean Jones, Diane Baker, Ellen Janov, Kurt Russell, Lurene Tuttle and Fred Clark in his final film role. It is based on the 1965 book The Year of the Horse by Eric Hatch. The film's title is a humorous reference to the titular horse's color and the title of the 1955 Sloan Wilson novel (and 1956 film) about the American search for purpose in a world dominated by business, The Man in the Gray Flannel Suit.

The film was paired with the animated featurette Winnie the Pooh and the Blustery Day in its original theatrical release but failed at the box office, and it received mostly negative reviews for its predictable script.