This study used data from the National Institute of Child Health and Human Development's Study of Early Child Care and Youth Development to examine relations between parenting, self-control, and externalizing behavior from infancy through 5th grade. Results indicate that self-control measured during middle childhood mediates relations between maternal sensitivity, opportunity for productive activity, and parental harshness and both mother-reported and teacher-reported externalizing behavior. Results showed that parenting measured during middle childhood was more strongly related to 5th-grade externalizing behavior compared with parenting measured during infancy and early childhood. However, there was evidence that parenting during the preschool years was related to 5th-grade externalizing behavior through later parenting and self-control.