An emblematic music of Louisiana, which is rooted in the ballads of the French-speaking Catholics of Canada. Cajun music is often mentioned in tandem with the Creole-based, Cajun-influenced Zydeco form, both of Acadiana origin (the official name given to the French Louisiana region that is home to a large Cajun population). These French Louisiana sounds have influenced American popular music for many decades, especially country music, and have influenced pop culture through mass media, such as television commercials.

The earliest form of Cajun music was the unaccompanied ballad. Standard versions of songs started to emerge with increasing sales of phonograph recordings. Some of the earliest recordings of Cajun music that exist were done in the late 1920s by noted historian Alan Lomax of farmhands in Louisiana.

The early songs were mixtures of la la, contredanses, reels and jigs and other folk influences from black, white and Native American traditions. Early song lyrics were entirely in old Cajun French. Though French language is still common, some Cajun music today is sung in English with younger singers and audiences.

In earlier years, the fiddle was the predominant instrument. Two fiddles were commonly used, one playing the melody while the other providing the séconde, or back-up part. Twin fiddling traditions represent the music in its purest form, as it was brought to Louisiana with the early immigrants and before popular American tunes mingled with it.

Gradually, the diatonic accordion emerged to share the limelight. The introduction of the accordion can be traced back to German Coast settlers.

In the early 1930s, the accordion was pushed into the background by the popular string sounds of the time. Mandolins, pianos and banjos joined fiddles to create a jazzy swing beat strongly influenced by the Western swing of neighbouring Texas. After WWII, the accordion regained its popularity in Cajun music.

Also, in the late 1930s and 1940s, country music became the dominant influence on Cajun music and bass and steel guitars were used.

Modern Cajun music began taking on the influence of jazz and modern country music, resulting in a more polished sound. The acoustic guitar was added, mostly as a rhythm instrument, and the triangle provided a traditional percussion. Modern groups sometimes include drums, electric bass, electric guitars and amplified accordion and fiddles.