William Martin Joel (born May 9, 1949) is an American singer, songwriter and pianist. Nicknamed the "Piano Man" after his signature 1973 song of the same name, Joel has had a successful career as a solo artist since the 1970s. From 1971 to 1993, he released 12 studio albums spanning the genres of pop and rock, and in 2001 released a one-off studio album of classical compositions. With over 160 million records sold worldwide, Joel is one of the world's best-selling music artists and is the fourth-best-selling solo artist in the United States. His 1985 compilation album, Greatest Hits – Volume I & Volume II, is one of the best-selling albums in the United States.

Joel was born in the Bronx in New York City and grew up on Long Island, where he began taking piano lessons at his mother's insistence. After dropping out of high school to pursue a music career, Joel took part in two short-lived bands, the Hassles and Attila, before signing a record deal with Family Productions and embarking on a solo career with his debut album, Cold Spring Harbor (1971). In 1972, Joel caught the attention of Columbia Records after a live radio performance of "Captain Jack" became popular in Philadelphia, prompting him to sign a new record deal with the company, through which he released his second album, Piano Man (1973). After Streetlife Serenade (1974) and Turnstiles (1976), Joel achieved his critical and commercial breakthrough with The Stranger (1977). It became Columbia's best-selling release, selling over 10 million copies and spawning the hit singles "Just the Way You Are", "Movin' Out (Anthony's Song)", "Only the Good Die Young", and "She's Always a Woman", as well as the concert staples "Scenes from an Italian Restaurant" and "Vienna".

52nd Street (1978) was Joel's first album to reach No. 1 on the Billboard 200. Glass Houses (1980) was an attempt to further establish himself as a rock artist; it featured "It's Still Rock and Roll to Me" (Joel's first single to top the Billboard Hot 100), "You May Be Right", "Don't Ask Me Why", and "Sometimes a Fantasy". The Nylon Curtain (1982) stemmed from a desire to create more lyrically and melodically ambitious music. An Innocent Man (1983) served as an homage to genres of music that Joel had grown up with in the 1950s, such as rhythm and blues and doo-wop; it featured "Tell Her About It", "Uptown Girl", and "The Longest Time", three of his best-known songs. After River of Dreams (1993), he largely retired from producing studio material, although he went on to release Fantasies & Delusions (2001), featuring classical compositions composed by him and performed by British-Korean pianist Richard Hyung-ki Joo. Joel provided voiceover work in 1988 for the Disney animated film Oliver & Company, performing the song "Why Should I Worry?", and contributed to the soundtracks to several films, including Easy Money (1983), Ruthless People (1986), and Honeymoon in Vegas (1992). Joel returned to composing new music with the 2024 single “Turn the Lights Back On”.

Joel has had a successful touring career, holding live performances across the globe. In 1987, he became one of the first artists to hold a rock tour in the Soviet Union. Joel has produced 33 self-written Top 40 hits in the U.S., three of which ("It's Still Rock and Roll to Me", "Tell Her About It", and "We Didn't Start the Fire") topped the Billboard Hot 100. Joel has been nominated for 23 Grammy Awards, winning 6, including Album of the Year for 52nd Street. Joel was inducted into the Songwriters Hall of Fame in 1992, the Rock and Roll Hall of Fame in 1999 and the Long Island Music Hall of Fame in 2006. He received the 2001 Johnny Mercer Award from the Songwriters Hall of Fame and was recognized at the 2013 Kennedy Center Honors.