Using longitudinal, multi-informant data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, the present study tested associations between trajectories of parental and child depressive symptoms from ages 11 to 15 years. Consistent with predictions, changes in mothers' and fathers' depressive symptoms were positively associated with change in children's depressive symptoms over time. In addition, youth characteristics of sex and pubertal development moderated the trajectories, with children more advanced on pubertal development showing higher initial levels of depressive symptoms, and girls demonstrating steeper slopes of depressive symptoms over time. The context of interparental relationship functioning (i.e., marital conflict, marital conflict resolution) moderated both the trajectories of child depressive symptoms and the interplay between parental and child depressive symptoms in ways largely consistent with hypotheses. Implications of the findings are discussed in terms of treating youth depressive symptoms with a consideration of the broader family context, including parental and interparental functioning.