This paper aimed to investigate the relationship between components of social capital (security, trust, social norms, social networks and participation in social activities) and physical activity participation among the adolescent students in Yazd city. The statistical population of the study included adolescent students (14-17 years old) from Yazd city. 382 adolescents were randomly selected through multistage cluster sampling. Data are gathered by social capital and physical activity participation questionnaires. Results of multivariate regression analysis showed that for boys, the components of social networks and security explained the greatest amount of variance of participation in physical activity while for girls, component of social networks explained the greatest amount of variance of participation in physical activity. Generally, the findings showed that boys who were more interested in social participation pay more attention to physical activities in comparison with female students.