Schools are increasingly involved in efforts to promote health and healthy behavior among their adolescent students, but are healthier students better learners? This synthesis of the empirical, longitudinal literature investigated the effects of the most predominant health-related behaviors--namely, alcohol and marijuana use, smoking, nutrition, physical activity, sexual intercourse, bullying, and screen time use (television, Internet, video games)--on the academic performance of adolescents. Thirty studies dating back to 1992 were retrieved from the medical, psychological, educational, and social science literature. Healthy nutrition and team sports participation were found to have a positive effect on academic performance, whereas the effects of alcohol use, smoking, early sexual intercourse, bullying, and certain screen time behaviors were overall negative. Generally, all relations of health-related behaviors and academic performance were dependent on contextual factors and were often mediated by psychosocial problems, social structures, and demographics. Findings were interpreted with use of sociological theories.