Examined the associations among peer relations, antisocial behavior, academic skill deficit, and family ecology with 2 cohorts of 102 and 104 9- and 10-yr-olds and their families. Teachers rated the boys on the Child Behavior Checklist, boys and parents were interviewed, and boys and their families were observed in their homes. Rejected boys experienced poorer family management practices, and displayed more behavioral and academic problems than did their average peers. The hypothesis that the effect of poor parent discipline on peer rejection was mediated by the boys’ antisocial behavior and academic skill deficits provided a better fit to the data than did the model in which poor discipline directly affected peer rejection.