Diane Cilento AM (born 5 October 1933 in Brisbane, Australia), is a theatre and film actress.

Her parents, Sir Raphael Cilento and Lady (Phyllis) Cilento, were both distinguished medical practitioners. At a young age, she decided to follow a career as an actress, and moved to the United Kingdom in the early 1950s. She soon secured roles in British films and steadily worked until the end of the decade without making a major impression with film audiences.

She was nominated for the Academy Award for Best Supporting Actress for her performance in Tom Jones in 1963 and appeared in The Third Secret the following year, but she allowed her film career to decline following her marriage to actor Sean Connery, the second of her three husbands, to whom she was married from 1962 to 1973. They are the parents of actor Jason Connery. In Connery's James Bond film You Only Live Twice, she doubled for her husband's co-star Mie Hama in a diving scene because Hama was indisposed.