Social interactions involve both cooperation to achieve a shared goal and competition over shared resources and rewards. The ability to engage in inter-personal coordination is an important measure of socio-emotional and cognitive well-being. Both cooperation and competition require interpersonal coordination, however with different motivational backgrounds. Competition is defined by a higher level of extrinsic motivation, while cooperation is related to more intrinsic motivation. In the context of the parent-child dyad, each individual has different motivations and contributions to the dyad. The parent’s and child’s sense of competitiveness and contribution to inter-personal synchrony will presumably differ from each other and adapt to one another. The current research employed Motion Energy Analysis, an objective measure of coordination of movements between individuals, to measure motor in-phase and anti-phase synchrony during parent-child cooperative and competitive play, with a focus on parent and child-led synchrony. Findings highlight that parents rate themselves as less competitive than their children rate themselves; with no such difference noted in cooperation. Further, parent-led motor synchrony is defined more by in-phase coordination in competition, especially when the interaction is novel. Alternatively, child-led motor synchrony is more anti-phase during competition. In cooperation parents and children lead synchrony to the same extent and in the same phase. Current findings highlight that parent’s and children uniquely adjust their leading behaviors in synchrony in competition, presumably adjusting their behavior to accommodate a complex situation. Given the importance of cooperative and competitive interactions to overall social well-being, and the parent’s role of modeling behaviors for their child, findings may direct future guidance and treatment plans that will promote social development.