This article examines policy towards juvenile delinquency in colonial Kenya in the interwar period, arguing that juvenile offenders were the subject of scant official interest until the 1930s, when a series of official reports was commissioned and legislation enacted which attempted to modernize the management of juvenile offenders in keeping with current metropolitan policy. This impulse for reform is placed in the context of colonial discourses on eugenics and the effects of urbanization and detribalization on young Africans, arguing that while key metropolitan principles about delinquency retained their influence on transferral to the colony, they were blended with a distinctive colonial rhetoric about African psychology and capacity for development.