The current study investigated the relations among parent-child joint engagement, dyadic interactive behaviors, and children's subsequent social competence with peers. Participants were 40 children (20 children with autism, and 20 developmentally-matched typical children) between the ages of 2.75 and 6.5 years. Observational coding was conducted to assess children's joint engagement initiations, global interactive behaviors with parents, and parents' responsiveness, behavior regulation, and attention regulation. Children's social competence with peers was measured approximately one year later. Group differences were observed in child-initiated joint engagement, children's interactive behaviors in the parent-child context, and individual aspects of social competence. Child-initiated joint engagement with parents was positively related to social competence with peers overall, and with less exclusion by peers and hyperactive-distractible behaviors with peers, in particular. In addition, parent attention regulation emerged as the most salient predictor of children's behaviors within the parent-child context. Findings are discussed with respect to implications for future research and intervention. (Contains 2 tables.)