Margaret Tyzack (9 September 1931 – 25 June 2011) was an English actress. Her television roles included The Forsyte Saga (1967) I, Claudius (1976), and George Lucas's Young Indiana Jones (1992–1993). She won the 1970 BAFTA TV Award for Best Actress.
In EastEnders, she portrayed Lydia Simmonds for two episodes in 2011. She had to pull out of the role for personal reasons.