Jazz played by a small ensemble featuring collective and solo improvisation. The term is often ascribed especially to the New Orleans pioneers of jazz, although many critics of popular music believe the term better describes the music of a later wave of white Chicago musicians including Jimmy McPartland, Bud Freeman, and Frank Teschemacher. The earliest jazz ensembles grew out of the ragtime and brass bands of New Orleans, incorporating elements of the blues. In early jazz ensembles, such as those led by King Oliver and Jelly Roll Morton, the trumpet or cornet plays the melody, with clarinet and trombone providing accompaniment. The tension created by soloists contrasts with the release of ensemble refrains. It is played with a distinctive two-beat rhythm, resulting in a joyous cacophony at fast tempos or slow, mournful dirges. Dixieland groups usually include banjo, tuba, and drums (Britannica Concise Encyclopedia).

The term Dixieland became widely used after the advent of the first million-selling hit records of the Original Dixieland Jazz Band in 1917. The music has been played continuously since the early part of the 20th century. Louis Armstrong's All-Stars was the band most popularly identified with Dixieland, although Armstrong's own influence runs through all of jazz.

The swing era of the 1930s led to the end of many Dixieland Jazz musicians' careers. Only a few musicians were able to maintain popularity. Most retired.

There was a revival of Dixieland in the late 1940s and 1950s, which brought many semiretired musicians a measure of fame late in their lives as well as bringing retired musicians back onto the jazz circuit after years of not playing (e.g. Kid Ory). Many Dixieland groups of the revival era consciously imitated the recordings and bands of decades earlier. Other musicians continued to create innovative performances and new tunes. For example, in the 1950s a style called "Progressive Dixieland" sought to blend traditional Dixieland melody with bebop-style rhythm. Steve Lacy played with several such bands early in his career. This style is sometimes called "Dixie-bop".

While the term Dixieland is still in wide use, the term's appropriateness is a hotly debated topic in some circles. For some it is the preferred label (especially bands on the USA's West coast and those influenced by the 1940s revival bands), while others (especially New Orleans musicians, and those influenced by the African-American bands of the 1920s) would rather use terms like Classic Jazz or Traditional Jazz. Some of the latter consider Dixieland a derogatory term implying superficial hokum played without passion or deep understanding of the music.

Today there are three main active streams of Dixieland jazz:

• Chicago style (Jimmy McPartland, Eddie Condon, Muggsy Spanier Bud Freeman) differs from its southern origin by being faster paced, resembling the hustle-bustle of city life; The rhythm sections of these bands substitute the string bass for the tuba and the guitar for the banjo. Musically, the Chicagoans play in more of a swing-style 4-to-the-bar manner.

• West Coast Revival The "West Coast revival" is a movement begun in the late 1930s by the Lu Watters Yerba Buena Jazz Band of San Francisco and extended by trombonist Turk Murphy. It started out as a backlash to the Chicago style, which is closer in development towards swing. The repertoire of these bands is based on the music of Joe "King" Oliver, Jelly Roll Morton, Louis Armstrong, and W.C. Handy. Bands playing in the West Coast style use banjo and tuba in the rhythm sections, which play in a 2-to-the-bar rhythmic style.

• New Orleans Traditional The "New Orleans Traditional" revival movement began with the rediscovery of Bunk Johnson in 1942 and was extended by the founding of Preservation Hall in the French Quarter during the 1960s. Bands playing in this style use string bass and banjo in the rhythm section playing 4-to-the-bar and feature popular tunes and Gospel hymns that were played in New Orleans since the early 20th century.