Oscar Emmanuel Peterson (August 15, 1925 – December 23, 2007) was a Canadian jazz pianist and composer. As a virtuoso who is considered to be one of the greatest jazz pianists of all time, Peterson released more than 200 recordings, won eight Grammy Awards, as well as a lifetime achievement award from the Recording Academy, and received numerous other awards and honours. He played thousands of concerts worldwide in a career lasting more than 60 years. He was called the "Maharaja of the keyboard" by Duke Ellington, simply "O.P." by his friends, and was informally known in the jazz community as "the King of inside swing".

Peterson worked in duos with Sam Jones, Niels-Henning Ørsted Pedersen, Joe Pass, Irving Ashby, Count Basie, and Herbie Hancock. He considered the trio with Ray Brown and Herb Ellis "the most stimulating" and productive setting for public performances and studio recordings. In the early 1950s, he began performing with Brown and drummer Charlie Smith as the Oscar Peterson Trio. Shortly afterward Smith was replaced by guitarist Irving Ashby, who had been a member of the Nat King Cole Trio. Ashby, who was a swing guitarist, was soon replaced by Barney Kessel. Their last recording, On the Town with the Oscar Peterson Trio (1958), recorded live at the Town Tavern in Toronto, was said to have captured a remarkable degree of emotional as well as musical understanding among three players.

Peterson won eight Grammy Awards during his lifetime between 1975 and 1997. He is considered among the best jazz pianists and jazz improvisers of the twentieth century.