Drawing on family systems theory, this study examined whether social cohesion with grandparents moderated the intergenerational transmission of depressive symptoms from mothers to their adolescent and young adult children. We analyzed data from 2,280 grandchildren and their mothers who participated in two waves of the National Survey of Families and Households. Results revealed that grandchildren who were least integrated with their grandparents resembled their mothers in the severity of depressive symptoms. Grandchildren who were more integrated with their grandparents bore no such resemblance. We conclude that grandparents are consequential family actors who, by conditioning parent-child dynamics, influence the long-term emotional well-being of their grandchildren. Results are discussed in terms of intergenerational interdependence and the untapped resource that older adults represent.