Jacques Joseph O'Mahoney, known professionally as Jock Mahoney, was an American actor and stuntman. He starred in two Action/Adventure television series, The Range Rider and Yancy Derringer. He played Tarzan in two feature films and was associated in various capacities with several other Tarzan productions. He was credited variously as Jacques O'Mahoney, Jock O'Mahoney, Jack Mahoney, and finally Jock Mahoney.

Yancy Derringer is an American action/adventure series that was broadcast on CBS from October 2, 1958, to September 24, 1959, with Jock Mahoney in the title role. It was broadcast from 8:30 to 9 p.m. Eastern Time on Thursdays.