Boris Karloff was born William Henry Pratt on 23 November 1887, at 36 Forest Hill Road, Camberwell, Surrey (now London), England, but Pratt stated that he was born in nearby Dulwich. His parents were Edward John Pratt, Jr. and Eliza Sarah Millard. His brother, Sir John Thomas Pratt, was a British diplomat. Edward John Pratt, Jr. was an Anglo-Indian, from a British father and Indian mother, while Karloff's mother also had some Indian ancestry, thus Karloff had a relatively dark complexion that stood out in British society at the time. His mother's maternal aunt was Anna Leonowens, whose tales about life in the royal court of Siam (now Thailand) were the basis of the musical The King and I. Pratt was bow-legged, had a lisp, and stuttered as a young boy. He conquered his stutter, but not his lisp, which was noticeable throughout his career in the film industry.
Pratt spent his childhood years in Enfield, in the County of Middlesex. He was the youngest of nine children, and following his mother's death was brought up by his elder siblings. He received his early education at Enfield Grammar School, and later at the private schools of Uppingham School and Merchant Taylors' School. After this, he attended King's College London where he took studies aimed at a career with the British Government's Consular Service. However, in 1909, he left university without graduating and drifted, departing England for Canada, where he worked as a farm labourer and did various odd itinerant jobs until happening upon acting.