Lock Martin, American actor (d. 1959)
Joseph Lockard "Lock" Martin Jr. (October 12, 1916 – January 19, 1959) was an American performer afflicted with giantism, best remembered for essaying the part of the robot Gort in The Day the Earth Stood Still (1951).

He was from Pennsylvania and had a series of jobs related to his height, e.g. he directed traffic at Bob's Big Boy drive-in restaurant in Van Nuys, CA in 1951. He also travelled with Spike Jones and His City Slickers and appeared on their television show in the early 1950s. He was regularly employed as a doorman at Grauman's Chinese Theater in Los Angeles when he was hired for the role of Gort, although this was not his first acting job.

He was also filmed for a part in The Incredible Shrinking Man as a circus giant, but his scenes were deleted.

He was reportedly 7 feet 7 inches tall (about 231 cm); however Robert Wise, director of The Day The Earth Stood Still, remembered his height as 7 feet 1 inch (about 216 cm) in the DVD commentary. His height did not equate with strength, however, and he had difficulty managing his robot suit. For scenes where he was supposed to physically lift Patricia Neal and Michael Rennie, they were either held up by wires, a hidden dolly or replaced with lightweight dummies.

He was nicknamed "the Gentle Giant" as he liked reading stories to children and for a time had a local show devoted to that. Martin was married to Ethel Babcock from 1946 until his death in 1959.