Jazz fusion is a musical genre that merges jazz with elements of other styles of music, particularly funk, rock, R&B, electronic, and world music, but also pop, classical, and folk music, or sometimes even metal, reggae, country, hip hop, etc. Fusion albums, even those that are made by the same group or artist, may include a variety of styles.

In the late 1960s, jazz musicians began mixing the forms and improvisational techniques of jazz with the electric instruments of rock and the rhythms of soul and rhythm and blues. At the same time, some rock artists began adding jazz elements to their music. The 1970s were the most visible decade for fusion, but the style has been well represented during more recent times. Rather than being a codified musical style, fusion can be viewed as a musical tradition or approach. Some progressive rock music is also labeled as fusion.

Fusion music is typically instrumental, often with complex time signatures, metres, rhythmic patterns, and extended track lengths, featuring lengthy improvisations. Many prominent fusion musicians are recognized as having a high level of virtuosity, combined with complex compositions and musical improvisation in metres rarely seen in other Western musical forms, perhaps best recognized in the work of jazz composers Dave Brubeck and Don Ellis.

Fusion music generally receives little radio broadcast airplay in the United States, owing perhaps to its complexity, usual lack of vocals, and frequently extended track lengths. European radio is friendlier to fusion music, and the genre also has a significant following in Japan and South America. A number of Internet radio stations feature fusion music, including dedicated channels on services such as AOL Radio and Yahoo! Launchcast.