English stage and film actress known for her direct and unsentimental portrayals of intelligent and spirited women.

Hiller was educated at Winceby House School and at age 18 joined the Manchester Repertory Company, for which she acted and stage-managed for several years. She scored her first major success as Sally Hardcastle in Love on the Dole (London 1935, New York 1936), a play whose coauthor, Ronald Gow, she subsequently married. Her performance so impressed George Bernard Shaw (Shaw, George Bernard) that he asked her to play Joan of Arc in his Saint Joan at the 1936 Malvern Festival. Shaw later declared her independent and down-to-earth interpretation of Saint Joan as the definitive portrayal, and he was instrumental in securing for her the role of Eliza Doolittle in the film version of Pygmalion (1938), in which she turned in a brilliantly comic Academy Award-nominated performance. She was equally memorable as another Shaw heroine in the screen adaptation of Major Barbara (1941).

Hiller returned to the stage in 1943, and in 1946 she joined the Bristol Old Vic for a season. There she played Tess in her husband's adaptation of Thomas Hardy's Tess of the d'Urbervilles—a production later transferred to London, where critics praised her performance for its intelligence and lack of affectation. In The Heiress (1947–49), a stage adaptation of Henry James (James, Henry)'s Washington Square, her performance as the ill-used Catherine Sloper was noted for its uncompromising bitterness. This quality was also evident in one of Hiller's best film roles, that of a long-suffering hotel owner who carries on a troubled affair with an alcoholic guest in Separate Tables (1958). For this performance, she was awarded the Academy Award for best supporting actress.

During the 1960s and '70s Hiller supplemented her active stage career with several highly regarded film roles, including her portrayal of the domineering and possessive matron Gertrude Morel in Sons and Lovers (1960). For her performance as Lady Alice More in A Man for All Seasons (1966), she received an Oscar nomination. On stage, she won accolades for her portrayal of Queen Mary in Crown Matrimonial (1972), a play that chronicles the abdication crisis of Edward VIII. Her performance as Gunhild Borkman in an acclaimed London production of Henrik Ibsen (Ibsen, Henrik)'s John Gabriel Borkman (1975) also received excellent notices. In 1975 Hiller was created a Dame of the British Empire. She continued to appear on stage, screen, and television through the 1990s and gave one of the best performances of her later years as the irritable elderly Southern gentlewoman in a London production of Driving Miss Daisy (1988).