Björk Guðmundsdóttir ( BYURK, Icelandic: [pjœr̥k ˈkvʏðmʏntsˌtouhtɪr̥] ; born 21 November 1965), known mononymously as Björk, is an Icelandic singer, songwriter, composer, record producer, and actress. Noted for her distinct voice, three-octave vocal range, and eccentric public persona, she has developed an eclectic musical style over a career spanning four decades, drawing on electronica, pop, dance, trip hop, jazz, and avant-garde music. She is one of the most influential pioneers in electronic and experimental music.

Born and raised in Reykjavík, Björk began her music career at the age of 11 and gained international recognition as the lead singer of the alternative rock band the Sugarcubes by the age of 21. After the Sugarcubes disbanded in 1992, Björk gained prominence as a solo artist with her albums Debut (1993), Post (1995), and Homogenic (1997), collaborating with artists from a range of disciplines and genres, and exploring a variety of multimedia projects. Her later albums consist of Vespertine (2001), Medúlla (2004), Volta (2007), Biophilia (2011), Vulnicura (2015), Utopia (2017) and Fossora (2022).

With sales of over 40 million records worldwide, Björk is one of the best-selling alternative artists of all time. Several of her albums have reached the top 20 on the US Billboard 200 chart. Thirty-one of her singles have reached the top 40 on pop charts around the world, with 22 top 40 hits in the UK, including the top-10 singles "It's Oh So Quiet", "Army of Me", and "Hyperballad" and the top-20 singles "Play Dead", "Big Time Sensuality", and "Violently Happy". Her accolades and awards include the Order of the Falcon, five BRIT Awards, and 16 Grammy nominations. In 2015, Time named her one of the 100 most influential people in the world. Rolling Stone named her the 64th-greatest singer and the 81st-greatest songwriter of all time in 2023.

Björk starred in the 2000 Lars von Trier film Dancer in the Dark, for which she won the Best Actress Award at the 2000 Cannes Film Festival, and was nominated for the Academy Award for Best Original Song for "I've Seen It All". Björk has also been an advocate for environmental causes in Iceland. A retrospective exhibition dedicated to Björk was held at New York's Museum of Modern Art in 2015.