William James Dixon (July 1, 1915 – January 29, 1992) was an American blues musician, vocalist, songwriter, arranger and record producer. He was proficient in playing both the upright bass and the guitar, and sang with a distinctive voice, but he is perhaps best known as one of the most prolific songwriters of his time. Next to Muddy Waters, Dixon is recognized as the most influential person in shaping the post–World War II sound of the Chicago blues.

Dixon's songs have been recorded by countless musicians in many genres as well as by various ensembles in which he participated. A short list of his most famous compositions includes "Hoochie Coochie Man", "I Just Want to Make Love to You", "Little Red Rooster", "My Babe", "Spoonful", and "You Can't Judge a Book by the Cover". These songs were written during the peak years of Chess Records, from 1950 to 1965, and were performed by Muddy Waters, Howlin' Wolf, Little Walter, and Bo Diddley; they influenced a generation of musicians worldwide.

Dixon was an important link between the blues and rock and roll, working with Little Walter, Chuck Berry, and Bo Diddley in the late 1950s. In the 1960s, his songs were adapted by numerous rock artists. He received a Grammy Award and was inducted into the Blues Hall of Fame, the Rock and Roll Hall of Fame, and the Songwriters Hall of Fame.