Charles Walter Rainey III (born June 17, 1940) is an American bass guitarist who has performed and recorded with many well-known acts, including Aretha Franklin, Steely Dan, and Quincy Jones. Rainey is credited for playing bass on more than 1,000 albums, and is one of the most recorded bass players in the history of recorded music.

Rainey was born in Cleveland, Ohio, on June 17, 1940, and grew up in Youngstown. His parents were both amateur pianists. He learned viola, piano, and trumpet as a childand majored in brass instruments in college. He attended Lane College in Jackson, Tennessee. Rainey began playing bass guitar in the military.