Monkey Business is a 1931 American pre-Code comedy film. It is the third of the Marx Brothers' released movies (Groucho, Harpo, Chico and Zeppo), and the first with an original screenplay rather than an adaptation of one of their Broadway shows. The film also features Thelma Todd, Harry Woods and Ruth Hall. It is directed by Norman Z. McLeod with screenplay by S. J. Perelman and Will B. Johnstone. Much of the story takes place on an ocean liner crossing the Atlantic Ocean.