Nancy Ann Olson (born July 14, 1928) is an American actress. She received an Academy Award nomination for Best Supporting Actress for her portrayal of Betty Schaefer in Sunset Boulevard (1950). She co-starred with William Holden in four films, and also later appeared in Disney's The Absent-Minded Professor (1961) and its sequel, Son of Flubber (1963), as well as the disaster film Airport 1975 (1974).

Olson has been virtually retired from acting since the early 1980s, although she has made a few rare returns, most recently in 2014.