James Wesley Marsters (born August 20, 1962) is an American actor and musician, best known for his roles in cult television series. Marsters first came to the attention of the general public playing the popular character Spike, a platinum-blond English vampire in the television series Buffy the Vampire Slayer and its spin-off series, Angel from 1997 to 2004. Since then, he has gone on to play other science fiction roles, such as the alien supervillain Brainiac on Smallville and the omnisexual time traveller Captain John Hart in British science-fiction show Torchwood. In 2007, Marsters appeared in a supporting role in the mainstream movie P.S. I Love You and as the main antagonist, Piccolo, in the 2009 fantasy adventure film Dragonball Evolution.

Marsters was born in Greenville, California, the son of a former minister and social worker. He grew up with his brother and sister in Modesto, California. Dreaming about becoming an actor since he played Eeyore in Winnie the Pooh in fourth grade, James joined the theater group at Davis High School, acting in many plays including musicals. After graduation, Marsters studied at the Pacific Conservatory of the Performing Arts, 1980–1982, and Juilliard Drama School, 1982–1984. Marsters also has a son, Sullivan, born in 1996.

In an appearance on the Loveline radio show in early 2003 he spoke very negatively about the school and his experience at Juilliard, which he was "basically kicked out of", saying that they were not concerned about being entertaining and that it "wasn't an acting school, it was a speech school".