13th man or thirteenth man may refer to:
13th man (Canadian football), like the 12th man in 11-player forms of football, a reference to fans of a 12-player Canadian football team The 13th Man, a 1937 American mystery film The Thirteenth Man, a 1917 Italian drama silent film 13th man rule, a provision in the American Basketball Association rulebook allowing each 12-man team to dress an extra player