Minimal music (also called minimalism) is a form of art music or other compositional practice that employs limited or minimal musical materials. Prominent features of minimalist music include repetitive patterns or pulses, steady drones, consonant harmony, and reiteration of musical phrases or smaller units. It may include features such as phase shifting, resulting in what is termed phase music, or process techniques that follow strict rules, usually described as process music. The approach is marked by a non-narrative, non-teleological, and non-representational approach, and calls attention to the activity of listening by focusing on the internal processes of the music.

The approach originated on the West Coast of the United States in the late 1950s and early 1960s, particularly around the Bay Area, where La Monte Young, Terry Riley and Steve Reich were studying and living at the time. After the three composers moved to the East Coast, their music became associated with the New York Downtown music scene of the mid-1960s, where it was initially viewed as a form of experimental music called the New York Hypnotic School. In the Western art music tradition, the American composers Moondog, La Monte Young, Terry Riley, Steve Reich and Philip Glass are credited with being among the first to develop compositional techniques that exploit a minimal approach. The movement originally involved dozens of composers, although only five (Young, Riley, Reich, Glass, and later John Adams) emerged to become publicly associated with American minimal music; other lesser known pioneers included Dennis Johnson, Terry Jennings, Richard Maxfield, Pauline Oliveros, Phill Niblock, and James Tenney. In Europe, the music of Louis Andriessen, Karel Goeyvaerts, Michael Nyman, Howard Skempton, Éliane Radigue, Gavin Bryars, Steve Martland, Peter Michael Hamel, Henryk Górecki, Arvo Pärt and John Tavener exhibits minimalist traits.

It is unclear where the term minimal music originates. Steve Reich has suggested that it is attributable to Michael Nyman, an assertion that two scholars, Jonathan Bernard, and Dan Warburton, have also made in writing. Philip Glass believes Tom Johnson coined the phrase.

The word "minimal" was perhaps first used in relation to music in 1968 by Michael Nyman, who "deduced a recipe for the successful 'minimal-music' happening from the entertainment presented by Charlotte Moorman and Nam June Paik at the ICA", which included a performance of Springen by Henning Christiansen and a number of unidentified performance-art pieces. Nyman later expanded his definition of minimal music in his 1974 book Experimental Music: Cage and Beyond. Tom Johnson, one of the few composers to self-identify as minimalist, also claims to have been first to use the word as new music critic for The Village Voice. He describes "minimalism":

The idea of minimalism is much larger than many people realize. It includes, by definition, any music that works with limited or minimal materials: pieces that use only a few notes, pieces that use only a few words of text, or pieces written for very limited instruments, such as antique cymbals, bicycle wheels, or whiskey glasses. It includes pieces that sustain one basic electronic rumble for a long time. It includes pieces made exclusively from recordings of rivers and streams. It includes pieces that move in endless circles. It includes pieces that set up an unmoving wall of saxophone sound. It includes pieces that take a very long time to move gradually from one kind of music to another kind. It includes pieces that permit all possible pitches, as long as they fall between C and D. It includes pieces that slow the tempo down to two or three notes per minute.

Already in 1965 the art historian Barbara Rose had named La Monte Young's Dream Music, Morton Feldman's characteristically soft dynamics, and various unnamed composers "all, to a greater or lesser degree, indebted to John Cage" as examples of "minimal art", but did not specifically use the expression "minimal music".

The most prominent minimalist composers are La Monte Young, Terry Riley, Steve Reich, Philip Glass, John Adams, and Louis Andriessen. Others who have been associated with this compositional approach include Terry Jennings, Gavin Bryars, Tom Johnson, Michael Nyman, Michael Parsons, Howard Skempton, Dave Smith, James Tenney, and John White. Among African-American composers, the minimalist aesthetic was embraced by figures such as jazz musician John Lewis and multidisciplinary artist Julius Eastman.

The early compositions of Glass and Reich are somewhat austere, with little embellishment on the principal theme. These are works for small instrumental ensembles, of which the composers were often members. In Glass's case, these ensembles comprise organs, winds—particularly saxophones—and vocalists, while Reich's works have more emphasis on mallet and percussion instruments. Most of Adams's works are written for more traditional European classical music instrumentation, including full orchestra, string quartet, and solo piano.