Joseph Leslie Sample (February 1, 1939 – September 12, 2014) was an American jazz keyboardist and composer. He was one of the founding members of The Jazz Crusaders in 1960, whose name was shortened to "The Crusaders" in 1971. He remained a part of the group until its final album in 1991, and also the 2003 reunion album Rural Renewal.

Beginning in the late 1960s, he saw a successful solo career and guested on several recordings by other acts, including Miles Davis, George Benson, Jimmy Witherspoon, Michael Franks, B. B. King, Eric Clapton, Steely Dan, Joni Mitchell, Anita Baker, Herb Alpert, and The Supremes. Sample incorporated gospel, blues, jazz, latin, and classical forms into his music.

Sample was born in Houston, Texas, the youngest son of Alexander Sample, a mail-carrier, and Agatha (née Osborne) Sample, a seamstress. Sample began to play the piano at the age of five. He was a student of the organist and pianist (Theodore or T.) Curtis Mayo.

In high school in the 1950s, Sample teamed up with friends saxophonist Wilton Felder and drummer "Stix" Hooper to form a group called the Swingsters. While studying piano at Texas Southern University, Sample met and added trombonist Wayne Henderson and several other players to the Swingsters, which became the Modern Jazz Sextet and then the Jazz Crusaders, in emulation of one of the leading progressive jazz bands of the day, Art Blakey's Jazz Messengers. Sample never took a degree from the university; instead, in 1960, he and the Jazz Crusaders made the move from Houston to Los Angeles. He was a member of Phi Beta Sigma fraternity.

The group quickly found opportunities on the West Coast, making its first recording, Freedom Sound, in 1961 and releasing up to four albums a year over much of the 1960s. The Jazz Crusaders played at first in the dominant hard bop style of the day, standing out by virtue of their unusual front-line combination of saxophone (played by Wilton Felder) and Henderson's trombone. Another distinctive quality was the funky, rhythmically appealing acoustic piano playing of Sample, who helped steer the group's sound into a fusion between jazz and soul in the late 1960s. The Jazz Crusaders became a strong concert draw during those years.

While Sample and his bandmates continued to work together, he and the other band members pursued individual work as well. In 1969, Sample made his first recording under his own name; Fancy Dance featured the pianist as part of a jazz trio. In the 1970s, as the Jazz Crusaders became simply the Crusaders and branched out into popular sounds, Sample became known as a Los Angeles studio musician, appearing on recordings by Joni Mitchell, Marvin Gaye, Miles Davis, B. B. King, Randy Crawford, George Benson, Joe Cocker, Herb Alpert, Michael Franks, Anita Baker (1994) and Steely Dan. Sample was a founding member of the L.A. Express, which was started as the backing band for Tom Scott; however, both Sample and fellow Crusader Larry Carlton left after that group's first album. In 1975, Sample went into the studio with bassist Ray Brown and drummer Shelly Manne to produce a then state-of-the-art recording direct to disc titled The Three. About this time, Blue Note Records reissued some of the early work by the Jazz Crusaders as The Young Rabbits. This was a compilation of their recordings produced between 1962 and 1968.

The electric keyboard was fairly new in the 1960s, and Sample became one of the instrument's pioneers. He began to use the electric piano while the group retained their original name, and the group hit a commercial high-water mark with the hit single "Street Life" and the album of the same name in 1979. He released Swing Street Café with R&B guitarist David T. Walker in 1981.

The Crusaders, after losing several key members, broke up after recording Life in the Modern World for the GRP label in 1987. Despite the disbanding of the Crusaders, the members would join each other to record periodically over the years, releasing Healing the Wounds in the early 1990s. Felder, Hooper, and Sample recorded their first album, called Rural Renewal, as the reunited Crusaders group in 2003 and played a concert in Japan in 2004.