Leslie West (born Leslie Weinstein; October 22, 1945) is an American rock guitarist, vocalist, and songwriter. He is best known as a founding member and co-lead vocalist of the hard rock band Mountain.

West was born in New York City, to a Jewish family. He grew up in Hackensack, New Jersey, and in East Meadow, New York, Forest Hills, New York and Lawrence, New York. After his parents divorced, he changed his surname to West. His musical career began with the Vagrants, an R&B/blue-eyed soul-rock band influenced by the likes of the Rascals that was one of the few teenage garage rock acts to come out of the New York metropolitan area itself (as opposed to the Bohemian Greenwich Village scene of artists, poets and affiliates of the Beat Generation, which produced bands like The Fugs and The Velvet Underground). The Vagrants had two minor hits in the Eastern US: 1966’s “I Can’t Make a Friend” and a cover of Otis Redding‘s “Respect” the following year.

Some of the Vagrants’ recordings were produced by Felix Pappalardi, who was also working with Cream on their album Disraeli Gears. In 1969, West and Pappalardi formed the pioneering hard rock act Mountain, which was also the title of West’s debut solo album. Rolling Stone identified the band as a “louder version of Cream”. With Steve Knight on keyboards and original drummer N. D. Smart, the band appeared on the second day of the Woodstock Festival on Saturday, August 16, 1969 starting an 11-song set at 9 pm.