This study tested a series of actor-partner interdependence models of coparental communication and relational satisfaction among ex-spouses living in stepfamilies. Participants included 41 ex-spousal dyads (N = 82). Results revealed two actor-oriented models whereby ex-spouses’ supportive and antagonistic coparental communication predicted their own (but not their ex-spouse’s) relational satisfaction. A second set of models revealed that nonresidential parents’ supportive and antagonistic coparental communication with the residential stepparent predicted their own satisfaction with their ex-spouses, as well as their ex-spouse’s satisfaction with them (i.e., a partner effect). Importantly, the findings demonstrate the interdependence of coparenting relationships in stepfamilies, as supportive coparental communication between nonresidential parents and their exspouse’s new partner (i.e., the stepparent) predicted meaningful variance in relational satisfaction for both ex-spouses