Though the study of coparenting is still in its infancy, an explosion of coparenting research is in the wings. This paper identifies several emerging issues in coparenting theory and research to guide work in the years ahead, including issues in definition, conceptualization, and measurement; the interface between coparenting and adult development; and conceptual benefits that will accrue from studies of interadult coordination across diverse cultures and family systems. We emphasize that theory must lead empirical efforts, that across family systems the strongest coparental alliances are likely to be those in which the coparents both experience and provide support and solidarity for one another's parenting efforts with the children, and that measurement approaches need to be expanded so as to capture more comprehensively each family's organizational cooparenting structures and themes.