Using interdependence theory, this study tested a series of actor–partner interdependence models of coparental communication and relational satisfaction among stepparents and nonresidential parents in stepfamilies. Participants included 40 residential stepparent/nonresidential parent dyads (N = 80). Results revealed significant actor and partner effects for stepparents’ and nonresidential parents’ reports of supportive and antagonistic coparental communication and relational satisfaction. A second set of models examined stepparents’ and nonresidential parents’ coparental communication with the residential parent and revealed that nonresidential parents’ supportive and antagonistic coparental communication predicted their own satisfaction with the stepparent, as well as the stepparent’s satisfaction with them (i.e., a partner effect). Importantly, the findings demonstrate the interdependence of coparenting relationships in stepfamilies, as nonresidential parents’ coparental communication with their ex-spouses predicted meaningful variance in stepparents’ satisfaction with the nonresidential parent.