Mary Loretta Hartley is an American film and television actress. She is possibly best known for her roles in film as Elsa Knudsen in Sam Peckinpah's Ride the High Country (1962), Susan Clabon in Alfred Hitchcock's Marnie (1964), and Betty Lloyd in John Sturges' Marooned (1969). She has appeared extensively on television, with notable roles as Claire Morton in the ABC soap opera Peyton Place (1965), various roles in the CBS television western drama series Gunsmoke, and a series of commercials with James Garner in the 1970s and 1980s.

Ride the High Country is a 1962 American CinemaScope Western film directed by Sam Peckinpah and starring Randolph Scott, Joel McCrea, and Mariette Hartley. The supporting cast includes Edgar Buchanan, James Drury, Warren Oates, and Ron Starr. The film's script, though credited solely to veteran TV screenwriter N.B. Stone Jr., was – according to producer Richard E. Lyons – almost entirely the work of Stone's friend and colleague, William S. Roberts, and Peckinpah himself.