Hayley Atwell (born 1982) is an English actress. She was a sixth-former at the London Oratory School, West London, and then trained at the Guildhall School of Music and Drama, where she appeared as Rose in I Capture the Castle and Cassandra in Troilus and Cressida among her training roles.

Atwell made her silver screen debut in Woody Allen's Cassandra's Dream. She also has roles in the forthcoming films How About You and Brideshead Revisited. She will next work on The Duchess, a film about Georgiana, Duchess of Devonshire, in which she plays Lady Bess Foster.