The family environment has consistently been linked to childhood conduct problems and the development of serious delinquent behavior among youth. This chapter provides a brief overview of longitudinal evidence linking aspects of family structure/functioning (i.e., early motherhood, family size, single parenthood, caretaker changes, family socioeconomic status), caregiver characteristics (i.e., parental criminality, substance use/dependence, internalizing problems, and inter-parental conflict) and parenting practices (i.e., parental attachment/bonding, parental warmth, positive reinforcement, harsh/rejecting parenting, inconsistent discipline, parental control/monitoring) to the development of youth antisocial behavior. Several examples of how research related to family factors has been used to inform the creation of effective prevention and intervention efforts aimed at reducing youth delinquency are provided. A set of key methodological and theoretical challenges associated with conducting research on family factors is then discussed, including examining gene-by-family environment interactions, considering reciprocal parent-child influences, and integrating information collected using multiple methods/informants when assessing parenting practices. The chapter concludes by providing some recommendations for future studies designed to further advance our understanding of how family factors influence the early emergence and persistence of delinquent behavior from childhood into early adulthood.