Shah was born in Karachi, Sindh, Pakistan; a cricketing prodigy as an adolescent, Owais Shah began his career playing cricket for Wycombe House Cricket Club, breaking a number of club records. Owais scored a league 154 for the senior first XI when aged only 12. He won numerous awards for the club including the Ken Barrington National Cup. His maturity at a young age allowed him to work his way through both the England Youth and Middlesex Cricket County System. He made his first-class debut at age 17 in 1996 and won the NBC Denis Compton Award in 1997. In early 1998 he captained England to victory in the Under 19's World Cup in South Africa, and the following season he was captain of the England Under-19 cricket team for their "Test" match series at home against Pakistan. His selection for the England 'A' team that toured Australia in late 1998 at the age of 17 suggested he was on the verge of a call-up to England's Test side. However, two poor seasons followed, and despite being capped in 2000, by the end of that season—in which he made under 500 first-class runs—he could no longer command a place in the Middlesex first team. However, he made a return to form in 2001, averaging 41.60 and making his ODI debut against Australia at Bristol. Later that summer, he made 62 against Pakistan, and in 2001 Shah was named by the Cricket Writers' Club as their Young Cricketer of the Year. Owais attended Isleworth and Syon School for Boys, Lampton School (Hounslow) for his A Levels and is also a university graduate.

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