The epidemiology of child and adolescent mental health is rapidly evolving, necessitating urgent and coordinated responses across health, education, social services, and justice sectors. This commentary highlights key trends in adolescent mental health, emphasizing the shifting social, economic, and technological determinants shaping youth mental health. Recent evidence indicates a rise in mental health challenges, with increased gender disparities, heightened stress from academic pressures, social media exposure, and economic inequalities, among others, shaping adolescent mental health trajectories. Simultaneously, health systems are facing escalating demands for mental health care, compounded by workforce shortages and gaps in training to address emerging conditions such as digital addiction and societal withdrawal. The commentary underscores the importance of preventive, intersectoral, and life course approaches to mental health, advocating for increased investment in prevention, research, workforce development, and integrated care models. Addressing these issues requires evidence-based policies that consider cross-national differences and gendered trends while ensuring sustainable mental health systems for future generations. By prioritizing adolescent mental health within broader public health agendas, we can create a foundation for long-term well-being and social sustainability.