Joan Ann Hackett (March 1, 1934 – October 8, 1983) was an American actress of film, stage and television. She was nominated for the BAFTA Award for Best Foreign Actress for the 1966 film The Group, and starred in the 1967 western Will Penny. She went on to be nominated for the Academy Award for Best Supporting Actress and win the Golden Globe Award for Best Supporting Actress for the 1981 film Only When I Laugh. She also starred as Christine Mannon in the 1978 PBS miniseries version of Mourning Becomes Electra.