The temporal coordination of interpersonal behavior is a foundation for effective joint action with synchronized movement moderating core components of person perception and social exchange. Questions remain, however, regarding the precise conditions under which interpersonal synchrony emerges. In particular, with whom do people reliably synchronize their movements? The current investigation explored the effects of arbitrary group membership (i.e., minimal groups) on the emergence of interpersonal coordination. Participants performed a repetitive rhythmic action together with a member of the same or a different minimal group. Of interest was the extent to which participants spontaneously synchronized their movements with those of the target. Results revealed that stable coordination (i.e., in-phase synchrony) was most pronounced when participants interacted with a member of a different minimal group. These findings are discussed with respect to the functional role of interpersonal synchrony and the potential avenues by which the dynamics of rhythmic coordination may be influenced by group status.