Marianne Evelyn Gabriel Faithfull (born 29 December 1946) is an English rock singer. She achieved popularity in the 1960s with the release of her hit single "As Tears Go By" and became one of the lead female artists during the British Invasion in the United States.

Born in Hampstead, London, Faithfull began her career in 1964 after attending a party for the Rolling Stones, where she was discovered by Andrew Loog Oldham. Her debut album Marianne Faithfull (1965, released simultaneously with her album Come My Way), was a commercial success followed by a number of albums on Decca Records. From 1966 to 1970, she had a highly publicised romantic relationship with Mick Jagger. Her popularity was enhanced by her film roles, such as those in I'll Never Forget What's'isname (1967), The Girl on a Motorcycle (1968) and Hamlet (1969). However, her popularity was overshadowed by personal problems in the 1970s. During this time, she was anorexic, homeless and addicted to heroin.

Noted for her distinctive voice, Faithfull's previously melodic and higher-registered vocals (prevalent throughout her career in the 1960s) were affected by severe laryngitis, coupled with persistent drug abuse during the 1970s. This permanently altered her voice, leaving it raspy, cracked and lower in pitch. This new sound was praised as "whisky soaked" by some critics and seen as having helped to capture the raw emotions expressed in Faithfull's music.

After a long commercial absence, Faithfull made a comeback with the 1979 release of her critically acclaimed album Broken English. The album was a commercial success and marked a resurgence of her musical career. Broken English earned Faithfull a nomination for the Grammy Award for Best Female Rock Vocal Performance and is often regarded as her "definitive recording". She followed this with a series of albums, including Dangerous Acquaintances (1981), A Child's Adventure (1983) and Strange Weather (1987). Faithfull wrote three books about her life: Faithfull: An Autobiography (1994), Memories, Dreams & Reflections (2007) and Marianne Faithfull: A Life on Record (2014).

Faithfull received the World Lifetime Achievement Award at the 2009 Women's World Awards, and she was made a Commandeur of the Ordre des Arts et des Lettres by the government of France.