During adolescence, young people develop crucial capacity for emotion regulation, and family context can be a risk or protective factor for adolescents developing affective disorders. We leveraged data from the Florida Youth Substance Abuse Survey (N = 7664) to propose adolescent emotion regulation as a mediator between family conflict, family protection, and adolescent depressive symptoms in the social development model. Latent moderated structural equation modeling revealed that adolescent regulation of negative emotions mediated the relationship between family conflict and depressive symptoms--adolescents with higher family conflict had more emotion regulation difficulties and more depressive symptoms. Adolescent age was a moderator such that associations between family protective factors and reduced depression, and between family conflict and emotion regulation difficulties were weaker in high school compared to middle school. Findings highlight the importance of youth emotion regulation processes and family emotional context in reducing adolescent depressive symptoms.