Keira Knightley was born in Teddington, Greater London, England, the daughter of Sharman Macdonald, an award-winning playwright, and Will Knightley, a theatre and television actor. Knightley's father is English and Knightley's mother is Scottish and of half Welsh ancestry. She has an elder brother, Caleb, who was born in 1979. She lived most of her life in Richmond, attending Teddington School and Esher College.
Keira has dyslexia, but nevertheless was successful in school and was thus permitted to acquire a talent agent and pursue an acting career. Keira requested an agent as early as the age of three but got one when she turned six, from her mother as a reward for studying hard.
Keira Knightley has noted that she was "single-minded about acting" during her childhood. Keira performed in a number of local amateur productions including After Juliet (written by her mother) and US (written by her then drama teacher, Ian McShane, no relation to the Deadwood actor).