Stål Aanderaa (born 1 February 1931) is a Norwegian mathematician.
He was born in Beitstad. He took the mag.scient. degree in 1959, and his doctorate at Harvard University in 1966. He was a professor at the University of Oslo from 1978 to his retirement in 2001. He is a member of the Norwegian Academy of Science and Letters.
Aanderaa is one of the namesakes of the Aanderaa–Karp–Rosenberg conjecture.