Objective: To describe the relationship between family meals and adolescent mental health and determine whether the relationship differs by sex. Design: Secondary analyses of a cross-sectional survey. Participants: A total of 8,500 nationally representative students. Main Outcome Measures: Reynolds Adolescent Depression Scale; Strengths and Difficulties Questionnaire; World Health Organization Well-being Index. Analysis: Multiple regression models determined the relationships between family meals and mental health indicators; sociodemographic variables and family connection were included as covariates. Results: Approximately 60% of adolescents shared family meals >=5 times in the previous week, whereas 22% reported that they shared <= 2 meals in the previous week. Greater frequency of family meals was associated with fewer depressive symptoms (P < .001), fewer emotional difficulties (P < .001) and better emotional well-being (<.001). These relationships between family meals and depressive symptoms were attenuated by sex; the relationship was stronger for females than for males. Conclusions and Implications: Frequent family meals may have a protective effect on the mental health of adolescents, particularly for depressive symptoms in girls. Interventions that aim to increase the frequency of family meals are needed to evaluate whether family meals alone can have an emotional benefit for adolescents.