The National Board of Review Award for Best Actress is one of the annual film awards given by the National Board of Review of Motion Pictures.

Dame Olivia Mary de Havilland was a British and American actress. The major works of her cinematic career spanned from 1935 to 1988. She appeared in 49 feature films and was one of the leading actresses of her time. At the time of her death in 2020 at age 104, she was the oldest living and earliest surviving Academy Award winner and was widely considered as being the last surviving major star from the Golden Age of Hollywood cinema. Her younger sister was Oscar-winning actress Joan Fontaine.