David Lee Marks (born August 22, 1948) is an American guitarist, singer and songwriter, best known for being a member of the Beach Boys, first joining the band in February 1962. He played rhythm guitar and sang harmonies on their first four studio albums, Surfin' Safari (1962), Surfin' U.S.A. (1963), Surfer Girl (1963) and Little Deuce Coupe (1963). He quit the band in August 1963 after an argument with manager Murry Wilson. After his departure, he went on to front a band called The Marksmen, and play and record with various other acts, including Casey Kasem's Band Without a Name, The Moon, Delaney and Bonnie, Colours and Warren Zevon.

In 1997, Marks rejoined the band as a full-time member, filling in for Carl Wilson, who was suffering from lung cancer and could not continue touring. In 1999, Marks departed from the band once again, due to his own health issues. In 2012, Marks reunited with the remaining original members of the Beach Boys, playing guitar during the band's 50th anniversary tour and on the album That's Why God Made the Radio, and singing harmonies on the album's title track. Following the tour's completion, it was announced that he, Al Jardine and Brian Wilson would not continue touring with the band. Marks continued working with Wilson and Jardine on Wilson's solo performances, and his 2015 album No Pier Pressure.