"Billie Jean" is a dance-pop/R&B song by American recording artist Michael Jackson. It was written, composed, and co-produced by Jackson, and produced by Quincy Jones from the singer's second solo album, Thriller (1982). Originally disliked by Jones, the track was almost removed from the album after he and Jackson had disagreements regarding it. The song is well known for its distinctive bass line and Jackson's vocal hiccups. The song was mixed 91 times by audio engineer Bruce Swedien before he finalized the song with the second mix.

Following the successful chart performances of the single "The Girl Is Mine" and the album Thriller, "Billie Jean" was released on January 2, 1983, as the collection's second single. It became a worldwide commercial and critical success; "Billie Jean" was one of the best-selling singles of 1983, and topped both the US and UK charts simultaneously. In other countries, "Billie Jean" topped the charts of Spain and Switzerland, reached the top ten in Austria, Italy, New Zealand, Norway and Sweden, and initially peaked at number 45 in France. After Jackson's death in 2009, the song would reach number one in that territory. "Billie Jean" was certified platinum by the Recording Industry Association of America (RIAA) in 1989.

Awarded numerous honors—including two Grammy Awards, one American Music Award and an induction into the Music Video Producers Hall of Fame—the song and corresponding music video propelled Thriller to the status of best-selling album of all time. The song was promoted with a short film that broke down MTV's racial barrier as the first video by a black artist to be aired by the channel in heavy rotation, and an Emmy-nominated performance on Motown 25: Yesterday, Today, Forever, in which Jackson premiered "the moonwalk". The song was also promoted through Jackson's Pepsi commercials; during the filming of one commercial, Jackson's scalp was severely burned. Covered by modern artists, "Billie Jean" sealed Jackson's status as an international pop icon. Rolling Stone magazine ranked the song #58 in its list of the 500 Greatest Songs of All Time. It is the only song to appear on every version of the album King of Pop.