La Monte Thornton Young (born October 14, 1935) is an American composer, musician, and performance artist recognized as one of the first American minimalist composers and a central figure in post-war avant-garde music. He is best known for his exploration of sustained tones, beginning with his 1958 composition Trio for Strings. His compositions have called into question the nature and definition of music, most prominently in the text scores of his Compositions 1960. While few of his recordings remain in print, his work has inspired prominent musicians across various genres, including avant-garde, rock, and ambient music.

Young played jazz saxophone and studied composition in California during the 1950s, and subsequently moved to New York in 1960, where he was a central figure in the downtown music and Fluxus art scenes. He then became known for his pioneering work in drone music (originally called dream music) with his Theatre of Eternal Music collective, alongside collaborators such as Tony Conrad, John Cale, and his wife, the multimedia artist Marian Zazeela. In 1964, he began work on his unfinished improvisatory composition The Well-Tuned Piano, iterations of which he has performed throughout subsequent decades.

Young worked extensively with Zazeela between 1962 and her death in 2024; together, the two recorded, performed live, and developed the Dream House sound and light environment. Beginning in 1970, he and Zazeela studied under Hindustani singer Pandit Pran Nath. In 2002, Young and Zazeela formed the Just Alap Raga Ensemble with their disciple Jung Hee Choi.

Young was born in a log cabin in Bern, Idaho. As a child he was influenced by the droning sounds of the environment, such as blowing wind and electrical transformers. During his childhood, Young's family moved several times before settling in Los Angeles, as his father searched for work. He was raised as a member of the Church of Jesus Christ of Latter-day Saints. He graduated from John Marshall High School. Young began his music studies at Los Angeles City College, and transferred to the University of California, Los Angeles (UCLA), where he received a BA in 1958. In the jazz milieu of Los Angeles, Young played with notable musicians including Ornette Coleman, Don Cherry, Billy Higgins, and Eric Dolphy. He undertook additional studies at the University of California, Berkeley from 1958 to 1960. In 1959 he attended the Darmstadt International Summer Courses for New Music under Karlheinz Stockhausen, and in 1960 relocated to New York in order to study electronic music with Richard Maxfield at the New School for Social Research. His compositions during this period were influenced by Anton Webern, Gregorian chant, Indian classical music, Japanese Gagaku, and Indonesian gamelan music.

A number of Young's early works use the twelve-tone technique, which he studied under Leonard Stein at Los Angeles City College. (Stein had served as an assistant to Arnold Schoenberg when Schoenberg, the inventor of the twelve-tone method, taught at UCLA.) Young also studied composition with Robert Stevenson at UCLA and with Seymore Shifrin at UC Berkeley. In 1958, he developed the Trio for Strings, originally scored for violin, viola, and cello, and which presaged his later work. The Trio for Strings has been described as an "origin point for minimalism." When Young visited Darmstadt in 1959, he encountered the music and writings of John Cage. There he also met Cage's collaborator, pianist David Tudor, who subsequently would première some of Young's works. At Tudor's suggestion, Young engaged in a correspondence with Cage. Within a few months, Young was presenting some of Cage's music on the West Coast. In turn, Cage and Tudor included some of Young's works in performances throughout the U.S. and Europe. Influenced by Cage, Young at this time took a turn toward the conceptual, using principles of indeterminacy in his compositions and incorporating non-traditional sounds, noises, and actions.

Young moved to New York City in 1960. In the spring of 1961 he developed an artistic relationship with Fluxus founder George Maciunas at the electronic music course of Richard Maxfield at The New School. Maciunas would go on to design the book An Anthology of Chance Operations, an artist's book publication from the early 1960s, featuring experimental neodada art and music composition that used John Cage–inspired indeterminacy. It was edited by Young and DIY co-published in 1963 by Young and Jackson Mac Low. A few months earlier, in December 1960, Young had curated and organized a series of concert performances by members of the nascent Fluxus movement at the top-floor loft of Yoko Ono at 112 Chambers Street involving visual artists, musicians, dancers, and composers — mixing music, visual art, and performance together. These performances were attended by John Cage, Peggy Guggenheim, Max Ernst, and Marcel Duchamp, among other art world luminaries.

During this period, Young created short, haiku-like, conceptual but dreamlike scores — texts that have become associated with Fluxus. For example, Young's Compositions 1960 includes a number of unusual actions, some of them un-performable, and constituted an early form of poetic conceptual and post-conceptual art. Most examine a certain presupposition about the nature of music and art by carrying absurd Dada-like concepts to an extreme. One, Composition 1960 #10 to Bob Morris instructs: "draw a straight line and follow it" (a directive which Young has said has guided his life and work since). Another instructs the performer to build a fire. Another states that "this piece is a little whirlpool out in the middle of the ocean." Another says the performer should release a butterfly into the room. Yet another challenges the performer to push a piano through a wall. Composition 1960 #7 proved especially pertinent to his future endeavors: it consisted of a B, an F#, a perfect fifth, and the instruction: "To be held for a long time."

In 1962, based on his dream chord, Young wrote The Second Dream of the High-Tension Line Stepdown Transformer. One of The Four Dreams of China, the piece is based on four pitches, which he later gave as the frequency ratios: 36-35-32-24 (G, C, +C#, D), and limits as to which may be combined with any other. Most of his pieces after this point are based on select pitches, played continuously, and a group of long held pitches to be improvised upon. For The Four Dreams of China Young began to plan Dream House, a light and sound installation conceived as a dream chord "work that would be played continuously and ultimately exist as a 'living organism with a life and tradition of its own,'" where musicians would live and create music twenty-four hours a day. He formed the music collective Theatre of Eternal Music to realize Dream House and other pieces. The group initially included calligrapher and light artist Marian Zazeela (who married Young in 1963), Angus MacLise, and Billy Name. In 1964 the ensemble comprised Young and Zazeela, John Cale and Tony Conrad (a former Harvard mathematics major), and sometimes Terry Riley (voices). Since 1966 the group has seen many permutations and has included Garrett List, Jon Hassell, Alex Dea, and many others, including members of Young's 60s groups.