Billie Eilish, in full Billie Eilish Pirate Baird O'Connell, (born December 18, 2001, Los Angeles, California, U.S.), American singer-songwriter who first gained recognition in 2015 for the song "Ocean Eyes" and became, in 2020, the youngest person ever to win a Grammy for album of the year.

Eilish's parents were inspired by Hanson, a '90s pop band formed by a group of homeschooled brothers from Tulsa, Oklahoma, to teach their children at home and encourage them to explore passions outside of the traditional education framework. As a child, Eilish experimented with horseback riding, dance, and singing as a member of the Los Angeles Children's Chorus. In 2015 Eilish's senior brother, Finneas Baird O'Connell, who performs under the moniker FINNEAS, enlisted her to sing "Ocean Eyes," a song he had written and produced for his band at the time and later put online. The song quickly gained achievement, and Eilish signed with the boutique label Darkroom in the summer of 2016.

Darkroom released Eilish's Don't Smile at Me in August 2017, an eight-song EP written by Eilish and FINNEAS. The EP was reissued with a bonus track in December 2017; two more bonus tracks were added in later reissues. Following its release, Don't Smile at Me peaked at 14 on the Billboard 200 chart.

Eilish's music draws inspiration from hip-hop artists, for example, Childish Gambino and Tyler, the Creator. Her presentation album, When We All Fall Asleep, Where Do We Go?, was released on March 29, 2019, and reached number one on the Billboard 200 chart. The song "Bad Guy" from the album was Eilish's first number-one single on the Billboard Hot 100 chart, and it won a Grammy in 2020 for song of the year; the album won album of the year. In 2019 Eilish also released the single "Everything I Wanted,", and it later was awarded the Grammy for record of the year. The documentary Billie Eilish: The World's a Little Blurry appeared in 2021. Later that year Eilish released her second studio album, Happier than Ever, which was noted for its confessional songs, various which deal with the downside of her celebrity. Also in 2021 she wrote (with FINNEAS) and performed "No Time to Die" for the James Bond film of the same name; it received the Oscar for best original song.