Bereavement—the loss of a loved one through death—can be a significant mental health risk. Yet, whether and how specific bereavement exposures affect mental health remains underexplored. For instance, little is known about the relationship between sibling death and adolescent mental health and whether any association manifests because of bereaved parents' poor mental health. We use longitudinal Future of Families and Child Wellbeing Study data (n = 2970) to analyze linkages between sibling death, parents' depression, and adolescents' depressive symptoms. With information collected from biological mothers and adolescents, including the vital status of siblings who share the same biological mother, we focus specifically on maternal siblings and maternal depression. Regression results show that sibling death corresponds with adolescents’—specifically girls’—higher depressive symptoms, but mothers' post-bereavement depression reduces the association to non-significance.