Albert Ayler (/ˈaɪlər/; July 13, 1936 – November 25, 1970) was an American avant-garde jazz saxophonist, singer and composer.

After early experience playing R&B and bebop, Ayler began recording music during the free jazz era of the 1960s. However, some critics argue that while Ayler's style is undeniably original and unorthodox, it does not adhere to the generally accepted critical understanding of free jazz. In fact, Ayler's style is difficult to categorize in any way, and it evoked incredibly strong and disparate reactions from critics and fans alike. His innovations have inspired subsequent jazz musicians.

His trio and quartet records of 1964, such as Spiritual Unity and The Hilversum Session, show him advancing the improvisational notions of John Coltrane and Ornette Coleman into abstract realms where whole timbre, and not just mainly harmony with melody, is the music's backbone. His ecstatic music of 1965 and 1966, such as "Spirits Rejoice" and "Truth Is Marching In", has been compared by critics to the sound of a brass band, and involved simple, march-like themes which alternated with wild group improvisations and were regarded as retrieving jazz's pre-Louis Armstrong roots.