Michael John Berryman (born September 4, 1948) is an American character actor. Berryman was born with hypohidrotic ectodermal dysplasia, a rare condition characterized by the absence of sweat glands, hair, and nails; his unusual appearance allowed Berryman to build a career playing characters in a number of cult films, horror films, and B movies.

He first drew attention for his roles in Miloš Forman's One Flew Over the Cuckoo's Nest (1975) and Wes Craven's The Hills Have Eyes (1977). He has appeared in a wide variety of feature films and television series, including Star Trek, The X-Files, and Highway to Heaven, in which he played Satan.