J. B. Lenoir (March 5, 1929 – April 29, 1967) was an American blues guitarist and singer-songwriter, active in the Chicago blues scene in the 1950s and 1960s.

Lenoir was born in Monticello, Mississippi. His full given name was simply “J. B.”; the letters were not initials. Lenoir’s guitar-playing father introduced him to the music of Blind Lemon Jefferson, which became a major influence. During the early 1940s, Lenoir worked with the blues artists Sonny Boy Williamson II and Elmore James in New Orleans. He was later influenced by Arthur Crudup and Lightnin’ Hopkins.

Lenoir died on April 29, 1967, in Urbana, Illinois, at the age 38, of injuries he had suffered in a car crash three weeks earlier.