Muss 'Em Up is a 1936 American detective drama film directed by Charles Vidor from a screenplay by Erwin Gelsey. RKO Radio pictures premiered the film in New York City on February 1, 1936, with a nationwide opening on February 14. The film stars Preston Foster and Margaret Callahan, with a supporting cast which includes Alan Mowbray, Ralph Morgan, Big Boy Williams, and Maxie Rosenbloom.