Organized youth sports are one of the most popular leisure-time activities worldwide, and are also one of the most participated-in forms of physical activity among children and young people. This chapter aims to discuss extracurricular sports where participation is distinct from schooling and typically occurs in the after-school period and on weekends. The vast majority of literature pertaining to the correlates of sports participation hypothesizes that indices of health and health behaviors are the outcomes of participation in organized sports. Consistent associations have been documented between sports participation and various indicators of mental health. One model capable of explaining the bidirectional nature of relationships between sports participation and a range of health outcomes is the Conceptual Model of Health through Sport. Organized youth sports are an important source of physical activity for children and adolescents, and the effects of dropout are likely to be numerous.