Hard bop is a style of jazz that is an extension of bebop (or "bop") music. Journalists and record companies began using the term in the mid-1950s to describe a new current within jazz which incorporated influences from rhythm and blues, gospel music, and blues, especially in the saxophone and piano playing. David H. Rosenthal contends in his book Hard Bop that the genre is to a large degree the natural creation of a generation of black American musicians who grew up at a time when bop and rhythm and blues were the dominant forms of black American music and prominent jazz musicians like Tadd Dameron worked in both genres. Another major influence in this genre was Miles Davis.

Hard bop is sometimes referred to as "funky hard bop." The "funky" label refers to the rollicking, rhythmic feeling associated with the style. The descriptor is also used to describe soul jazz, which is commonly associated with hard bop. According to Mark C. Gridley, soul jazz more specifically refers to music with "an earthy, bluesy melodic concept and... repetitive, dance-like rhythms.... Note that some listeners make no distinction between 'soul-jazz" and 'funky hard bop,' and many musicians don't consider 'soul-jazz' to be continuous with 'hard bop.'" The term "soul" suggests the church, and traditional gospel music elements such as "amen chords" (the plagal cadence) and triadic harmonies seemed to suddenly appear in jazz during the era.

Hard bop first developed in the mid-1950s, and is generally seen as originating with The Jazz Messengers, a quartet led by pianist Horace Silver and drummer Art Blakey. Some saw hard bop as a response to cool jazz and west coast jazz. As Paul Tanner, Maurice Gerow, and David Megill explain, "the hard bop school... saw the new instrumentation and compositional devices used by cool musicians as gimmicks rather than valid developments of the jazz tradition." However, Shelly Manne suggested that cool jazz and hard bop simply reflected their respective geographic environments: the relaxed cool jazz style reflected a more relaxed lifestyle in California, while driving bop typified the New York scene. Some writers, such as James Lincoln Collier, suggest that the style was an attempt to recapture jazz as a form of African American expression. Whether or not this was the intent, many musicians quickly adopted the style, regardless of race. The hard bop style enjoyed its greatest popularity in the 1950s and 1960s, but hard bop performers, and elements of the music, remain popular in jazz. According to Nat Hentoff in his 1957 liner notes for the Blakey Columbia LP of the same name, the phrase "hard bop" was originated by author-critic-pianist John Mehegan, jazz reviewer of the New York Herald Tribune at that time.