This review examines the relationship between physical activity and mental health in children and adolescents, focusing on depression, anxiety, self-esteem, and cognitive functioning. The authors conducted a 'review of reviews' to synthesize evidence from 18 reviews and a brief analysis of sedentary behavior and mental health. Key findings include: 1. **Depression**: Physical activity may reduce depression, but the evidence is weak and intervention designs are often low in quality. 2. **Anxiety**: Physical activity interventions show a small beneficial effect for reduced anxiety, but the evidence base is limited. 3. **Self-Esteem**: Physical activity can improve self-esteem, especially in the short term, but there is a lack of high-quality research. 4. **Cognitive Functioning**: Routine physical activity is associated with improved cognitive performance and academic achievement, but these associations are typically small and inconsistent. 5. **Sedentary Behavior**: There is a consistent negative association between sedentary behavior and mental health, particularly screen time. The review highlights the need for more rigorous studies to establish causality and to explore the broader psychosocial benefits of physical activity in young people.This review examines the relationship between physical activity and mental health in children and adolescents, focusing on depression, anxiety, self-esteem, and cognitive functioning. The authors conducted a 'review of reviews' to synthesize evidence from 18 reviews and a brief analysis of sedentary behavior and mental health. Key findings include: 1. **Depression**: Physical activity may reduce depression, but the evidence is weak and intervention designs are often low in quality. 2. **Anxiety**: Physical activity interventions show a small beneficial effect for reduced anxiety, but the evidence base is limited. 3. **Self-Esteem**: Physical activity can improve self-esteem, especially in the short term, but there is a lack of high-quality research. 4. **Cognitive Functioning**: Routine physical activity is associated with improved cognitive performance and academic achievement, but these associations are typically small and inconsistent. 5. **Sedentary Behavior**: There is a consistent negative association between sedentary behavior and mental health, particularly screen time. The review highlights the need for more rigorous studies to establish causality and to explore the broader psychosocial benefits of physical activity in young people.