Young children’s social skills are rooted in children’s early relationships with their proximal caregivers, in particular the relationships with their mothers and fathers. One indicator of the parent-child relationship is the quality of their dyadic interactions. One factor that has been found to influence high quality parent-child interactions and children’s subsequent social competence is a parent’s psychological functioning Guided by the bioecological model, this study examined the longitudinal effects through which mothers’ and fathers psychological functioning (i.e., their depressive symptoms, role overload, and optimism) influenced their children’s social competence and problem behaviors through their dyadic synchrony during play in a sample of low-income families participating in a parenting intervention. It also tested the joint or combined effects of mothers’ and fathers’ psychological functioning on these pathways. The study is discussed with an eye towards future research, intervention, and policy efforts in including fathers as they remain an understudied and underutilized resource in promoting positive child development.