A recent trend shows that activity levels in children are declining while obesity levels are increasing. To address this problem, after school programs are being introduced to increase activity levels in preadolescents and promote healthy lifestyles. Existing studies have suggested that a better understanding of the psychosocial influences on physical activity (PA) during preadolescence could assist efforts in school settings to promote lifelong PA. This study used a sample of third grade students to investigate the relationships between the psychosocial correlates of PA, Gender, Extracurricular PA Participation, Intention to Be Physically Active, and BMI among third grade children. Results indicated that Gender, Beliefs (about the consequences of being active), and Self-Efficacy were associated with Extra Curricular PA Participation while Beliefs and Self-Efficacy were related to Intention to Be Physically Active. This suggests that third grade children’s Extra Curricular PA Participation and Intentions to Be Physically Active can be improved by enhancing children’s Self-Efficacy and Beliefs about the consequences of being active. / Fisher Institute for Wellness and Gerontology