Robert Marinus Lyden (May 28, 1942 – January 17, 1986) was a child actor in the 1950s.

The child actor is probably best-known for his role as the young space cadet "Bobby" on the 1954 science fiction television show Rocky Jones, Space Ranger.

After Rocky Jones (which lasted only two seasons), he made a few more television appearances, and had roles in some feature films.

He had a short role in The Searchers (1956), in which he played John Wayne's nephew Ben.

This turned out to be Lyden's last role; he left show business and pursued a career in finance.