The Modern Jazz Quartet (MJQ) was a jazz combo established in 1952 that played music influenced by classical, cool jazz, blues and bebop. The band performed over a 40-year span with only one personnel change. For the majority of their career, the group was composed of John Lewis (piano and musical director), Milt Jackson (vibraphone), Percy Heath (double bass) and Connie Kay (drums).

Under Lewis's leadership, they carved their own niche by specializing in elegant, restrained music that used sophisticated counterpoint, yet nonetheless retained a strong blues feel. Lewis firmly believed that J.S. Bach and the blues were compatible, combining classical form with jazz improvisation and polyphony. The band was also noted for its ability to play alongside a variety of other groups. Initially active into the 1970s until Jackson quit in 1974 due to creative disagreement and frustration with their busy touring schedule, the MJQ reformed intermittently into the 1990s.