Terrance Quinn, known professionally as Terry O'Quinn, is an American actor. He played John Locke on the TV series Lost, the title role in The Stepfather and Stepfather II, and Peter Watts in Millennium, which ran for three seasons (1996-1999). He has also hosted Mysteries of The Missing on The Science Channel.

O'Quinn began acting in the 1970s during his time as an undergraduate at Central Michigan University. He not only was an actor but also playwright/director.  Starting in 1980, O'Quinn has appeared in various feature films such as Silver Bullet, Tombstone, Heaven's Gate, Young Guns, alongside Rutger Hauer in Blind Fury, and as Howard Hughes in The Rocketeer.

His early television roles include guest appearances on Miami Vice, Moonlighting, Star Trek: The Next Generation, The Twilight Zone (1985 revival), Homicide: Life on the Street, a recurring role on Earth 2, another recurring role as Captain (& later Rear Admiral) Thomas Boone on JAG, as well as Colonel Will Ryan on the JAG spin-off series NCIS.  O'Quinn started acting in the television series Millennium as Peter Watts, and holds the distinction of having played four different characters within the extended X-Files/Millennium continuum.

Terry joined the Cameo platform shortly after its launch in 2017. He has since been creating videos for fans and donating all of the proceeds to the Virginia Beach SPCA. Terry has raised thousands of dollars on Cameo, and continues to create videos weekly.