Otis Spann (March 21, 1924 or 1930 – April 24, 1970) was an American blues musician, whom many consider to be the leading postwar Chicago blues pianist. Sources differ over Spann’s early years. Some state that he was born in Jackson, Mississippi, in 1930, but the researchers Bob Eagle and Eric LeBlanc concluded, on the basis of census records and other official information, that he was born in 1924 in Belzoni, Mississippi.

Spann’s father was, according to some sources, a pianist called Friday Ford. His mother, Josephine Erby, was a guitarist who had worked with Memphis Minnie and Bessie Smith, and his stepfather, Frank Houston Spann, was a preacher and musician. One of five children, Spann began playing the piano at the age of seven, with some instruction from Friday Ford, Frank Spann, and Little Brother Montgomery.

By the age of 14, he was playing in bands in the Jackson area. He moved to Chicago in 1946, where he was mentored by Big Maceo Merriweather. Spann performed as a solo act and with the guitarist Morris Pejoe, working a regular spot at the Tic Toc Lounge. Spann became known for his distinctive piano style. He replaced Merriweather as Muddy Waters’s piano player in late 1952 and participated in his first recording session with the band on September 24, 1953. He continued to record as a solo artist and session player with other musicians, including Bo Diddley and Howlin’ Wolf, during his tenure with the group. He stayed with Muddy Waters until 1968.