Carla Bley (born Lovella May Borg; May 11, 1936 – October 17, 2023) was an American jazz composer, pianist, organist, and bandleader. An important figure in the free jazz movement of the 1960s, she was perhaps best known for her jazz opera Escalator over the Hill (released as a triple LP set), as well as a book of compositions that have been performed by many other artists, including Gary Burton, Jimmy Giuffre, George Russell, Art Farmer, Robert Wyatt, John Scofield, and her ex-husband Paul Bley. She was a pioneer in the development of independent artist-owned record labels, and recorded over two dozen albums between 1966 and 2019.

Bley was born in Oakland, California, in 1936, to Swedish parents. Her father, Emil Borg, a piano teacher and church choirmaster, encouraged her to sing and to learn to play the piano; her mother, Arline Anderson, died of a heart attack when Bley was eight years old. After giving up church to immerse herself in roller skating at the age of fourteen, she moved to New York City at seventeen and became a cigarette girl at Birdland, where she met jazz pianist Paul Bley, who encouraged her to start composing.She toured with him under the name Karen Borg before changing her name in 1957 to Carla Borg. She married Bley and took his name the same year, later divorcing. She kept the surname professionally thereafter.