Callen Radcliffe Tjader Jr. (July 16, 1925 – May 5, 1982) was an American Latin Jazz musician, often described as the most successful non-Latino Latin musician. He explored other jazz idioms, especially small group modern jazz, even as he continued to perform music of Africa, the Caribbean and Latin America.

Tjader played the vibraphone primarily, and was accomplished on the drums, bongos, congas, timbales, and the piano. He worked with many musicians from several cultures. He is often linked to the development of Latin rock and acid jazz. Although fusing Jazz with Latin music is often categorized as "Latin Jazz", Tjader's works swung freely between both styles. His Grammy award in 1980 for his album La Onda Va Bien capped off a career that spanned over 40 years

Tjader soon quit Shearing after a gig at the San Francisco jazz club the Blackhawk. In April 1954, he formed the Cal Tjader Modern Mambo Quintet. The members were brothers Manuel Duran and Carlos Duran on piano and bass respectively, Benny Velarde on timbales, bongos, and congas, and Edgard Rosales on congas (Luis Miranda replaced Rosales after the first year). Back in San Francisco and recording for Fantasy Records, the group produced several albums in rapid succession, including Mambo with Tjader.

The Mambo craze reached its pitch in the late 1950s, a boon to Tjader's career. Unlike the exotica of Martin Denny and Les Baxter, music billed as "impressions of" Oceania (and other locales), Tjader's bands featured seasoned Cuban players and top-notch jazz talent conversant in both idioms. He cut several notable straight-ahead jazz albums for Fantasy using various group names, most notably the Cal Tjader Quartet (composed of bassist Gene Wright, drummer Al Torre, and pianist Vince Guaraldi). Tjader is sometimes lumped in as part of the West Coast (or "cool") jazz sound, although his rhythms and tempos (both Latin and bebop) had little in common with the work of Los Angeles jazzmen Gerry Mulligan, Chet Baker, or Art Pepper.

Tjader and his band opened the second Monterey Jazz Festival in 1959 with an acclaimed "preview" concert. The first festival had suffered financially. Tjader is credited with bringing in big ticket sales for the second and saving the landmark festival before it had even really started. The Modern Mambo Quintet disbanded within a couple of years. Tjader formed several more small-combo bands, playing regularly at such San Francisco jazz clubs as the Blackhawk.