William Alexander “Sonny” Greer (December 13, c. 1895 – March 23, 1982) was an American jazz drummer and vocalist, best known for his work with Duke Ellington.

Greer was born in Long Branch, New Jersey, United States, and played with Elmer Snowden‘s band and the Howard Theatre‘s orchestra in Washington, D.C., before joining Duke Ellington, whom he met in 1919. He was Ellington’s first drummer, playing with his quintet, the Washingtonians, and moved with Ellington into the Cotton Club. As a result of his job as a designer with the Leedy Drum Company of Indiana, Greer was able to build up a huge drum kit worth over a then-considerable $3,000, including chimes, a gong, timpani, and vibes.