Objective: The present study examined the role of family experiences in the early development and maintenance of oppositional defiant disorder (ODD) symptoms in preschool-age children with behavior problems. Method: Participants were 199 3-year-old children with behavior problems who took part in 4 annual child and family assessments. Results: Children with behavior problems who were exposed to overreactive parenting practices, maternal depression, marital conflict, and lower family income tended to have more ODD symptoms 3 years later. Moreover, initial changes in paternal overreactivity and changes in maternal depression corresponded to initial changes in ODD symptoms. Children who met criteria for attention-deficit/hyperactivity disorder at 6 years of age were less likely to show improvement in ODD symptoms from 3 to 6 years of age, and they were more likely to have been exposed to negative parenting practices, marital conflict, and parental depression during the preschool years. Maternal depression and overreactivity mediated the relation between early hyperactivity and later ODD symptoms. Conclusions: Results point to the importance of early family functioning in the development of ODD.