William Scott Gorham (born March 17, 1951) is an American guitarist and songwriter who was one of the "twin lead guitarists" for the Irish rock band Thin Lizzy. Although not a founding member of Thin Lizzy, he served a continuous membership after passing an audition in 1974, joining the band at a time when the band's future was in doubt after the departures of original guitarist Eric Bell and his brief replacement Gary Moore. Gorham remained with Thin Lizzy until the band's breakup in 1984. He and guitarist Brian Robertson, both hired at the same time, marked the beginning of the band's most critically successful period, and together developed Thin Lizzy's twin lead guitar style while contributing dual backing vocals as well. Gorham is the band member with the longest membership after founders Brian Downey (drummer) and frontman and bass guitarist, Phil Lynott.