Lou Donaldson (born November 1, 1926) is an American retired jazz alto saxophonist. He is best known for his soulful, bluesy approach to playing the alto saxophone, although in his formative years he was, as many were of the bebop era, heavily influenced by Charlie Parker.

Donaldson was born in Badin, North Carolina, United States. He attended North Carolina Agricultural and Technical State University in Greensboro in the early 1940s. He enlisted in the U.S. Navy during World War II and was trained at the Great Lakes bases in Chicago where he was introduced to bop music in the lively club scene.