AbstractIntergenerational coparenting has become an increasingly common family phenomenon across the globe. In this study, we examined the associations among depressive symptoms, perceptions of intergenerational coparenting relationships, and (grand)parenting behaviors. Participants were parents and grandparents most involved in child care from 464 Chinese coparenting families sampled in urban China. The results from a test of the actor–partner interdependence mediation model showed that the depressive symptoms of parents and grandparents were indirectly and positively related to their harsh discipline of children or negatively related to their supportiveness toward children, and the association was mediated via their own perceptions of the coparenting relationship. In addition, parents' depressive symptoms were indirectly and positively related to grandparental harsh parenting or negatively related to grandparental supportive parenting through grandparents' perceived coparenting relationship. Grandparents' depressive symptoms were indirectly and positively related to parental harsh parenting or negatively related to parental supportive parenting through parents' perceptions of the coparenting relationship. This study highlights the importance of uncovering the processes and dynamics of parent–grandparent coparenting practices through a lens of family systems and interdependence theories as well as a dyadic approach. It also has practical implications for family interventions in the context of intergenerational coparenting. Specifically, this study recommends parallel (grand)parenting intervention sessions for parents and grandparents simultaneously to benefit the well‐being of all three generations.