The intersection between eating behaviours and mental health has garnered substantial attention in recent years. For this Review, we systematically reviewed the available research to find out the prevalence of food addiction as measured by the Yale Food Addiction Scale, and to investigate its association with mental health-related outcomes in adolescents. Eight databases were searched using keywords from Jan 1, 2009, to Aug 5, 2020, to identify studies reporting a Yale Food Addiction Scale diagnosis or symptom score, or both. In total, 27 studies were included. The prevalence of a food addiction diagnosis ranged from 2·6% to 49·9% in non-clinical and clinical populations, and prevalence was higher in women and adolescents with a higher weight status. Food addiction was associated with disordered eating, depressive and anxiety symptoms, and a poorer quality of life and self-esteem. These associations have important implications for the assessment and management of eating behaviours and mental health in adolescents. Transdiagnostic prevention and management intervention strategies could be explored.