Sonny Boy Williamson (John Lee Curtis Williamson, March 30, 1914 – June 1, 1948) was an American blues harmonica player and singer, and the first to use the name Sonny Boy Williamson.

Williamson was born near Jackson, Tennessee in 1914. His original recordings were considered to be in the country blues style, but he soon demonstrated skill at making harmonica a lead instrument for the blues, and popularized it for the first time in a more urban blues setting. He has been called "the father of modern blues harp". While in his teens he joined Yank Rachell and Sleepy John Estes playing with them in Tennessee & Arkansas, and in 1934 settled in Chicago, Illinois.