The chapter first explains why atypical development in the preschool years has implications for child delinquency. It notes that psychological research has consistently found that socialization processes during early childhood -- including the development of self-control, perspective-taking, empathy, and problem-solving skills -- are linked to the development of antisocial behavior; however, there has been relatively little interdisciplinary effort to generate development paradigms for the study of the emergence of antisocial behavior. With a view toward developing such a paradigm, this chapter reviews typical and atypical development in aggression, noncompliance, and lying in early childhood, as well as child and family factors that influence the development of antisocial behavior. The discussion focuses on language development, temperamental characteristics, attachment to caregivers, parenting behaviors, and family adversity. The chapter concludes with a presentation of evidence for the prediction of childhood delinquency from preschool behaviors. The data presented in this chapter indicate that the majority of early-onset antisocial juveniles have histories of aggressive, inattentive, or sensation-seeking behaviors during their preschool years; however, the majority of preschoolers with behavioral problems do not become young offenders. It is important, therefore, to identify turning points in trajectories that distinguish future delinquents from children with problem behaviors who do not engage in subsequent delinquency. 2 figures and 1 table