The adolescent children of depressed mothers are at increased risk for depression, but little is known about protective factors for these children. Maintenance of positive affect in a stressful context may be an important marker of resilience. Mothers with (n = 34) and without (n = 38) a history of depression and their adolescent children completed questionnaires regarding adolescents' coping and depressive symptoms and engaged in a 15 min videotaped interaction about family stress. Adolescents' observed behaviors were coded using the Iowa Family Interaction Rating Scales. No significant differences emerged in observed behavior between adolescents of mothers with and without a history of depression. Higher levels of primary and secondary control coping and lower levels of disengagement coping were related to higher levels of observed positive mood and fewer depressive symptoms in adolescents. Observed positive mood was related to fewer depressive symptoms in adolescents, even after accounting for maternal history of depression and current maternal depressive symptoms. Results suggest the importance of considering positive affect in the context of family stress as a marker of resilience in adolescents at risk for depression. The current study provides evidence for coping as a protective factor, related to higher levels of positive affect and fewer depressive symptoms, in adolescents exposed to maternal depressive symptoms.