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.

Mildred Pierce is a 1945 American melodrama/film noir directed by Michael Curtiz and starring Joan Crawford, Jack Carson, and Zachary Scott, also featuring Eve Arden, Ann Blyth, and Bruce Bennett. Based on the 1941 novel by James M. Cain, this was Crawford's first starring role for Warner Bros., after leaving Metro-Goldwyn-Mayer, and she won the Academy Award for Best Actress. In 1996, Mildred Pierce was deemed "culturally, historically, or aesthetically significant" and selected for preservation in the United States Library of Congress National Film Registry.