James Blanco Martin (born July 21, 1961, in Hayward, California, a suburb of Oakland), professionally known as Big Jim Martin, is an American guitarist best known for his membership in the rock band Faith No More from 1983 to late 1993. He also played guitar with the groups Agents of Misfortune, The Behemoth, The Chickenfuckers, EZ-Street, Fang, Infectious Grooves, Pigs of Death, Recluse, Spastik Children, Vicious Hatred, and Voodoocult.

He was known for his long hair, bushy beard, and trademark red-rimmed glasses that he wears alone or over another darker pair of glasses.