Both law and society scholars and developmental psychologists have focused on the legitimacy of authority figures, although in different domains (police versus parents). The purpose of the current research is to bridge these two fields by examining the relations among parenting style (i.e., authoritarian, authoritative, permissive), the perception of parental legitimacy, and changes in delinquency over time. It is hypothesized that parental legitimacy mediates the relation between parenting style and future delinquent behavior. Middle school and high school students completed questionnaires three times over a period of 18 months. Parenting style and delinquent behavior were measured at time 1, parental legitimacy at time 2, and delinquency again at time 3. The results show that authoritative parenting was positively related to parental legitimacy, while authoritarian parenting was negatively associated with parental legitimacy. Furthermore, parental legitimacy was negatively associated with future delinquency. Structural equation modeling indicated that parental legitimacy mediated the relation between parenting styles and changes in delinquency over the 18-month time period. The implications for parenting style and parental legitimacy affecting delinquent behavior are discussed. (Contains 3 tables and 2 figures.)