In this study, the association between physical activity participation and self-efficacy for physical activity was measured in adolescent males. Also, the possibility that self-efficacy levels differed between school sport participants and non-school sport participants was explored. The results of the Spearman’s p test showed a moderate positive, and significant correlation between PAQ-A and SEPAQ scores, r(113) = .571, p < .01. The regression analysis showed that PAQ-A score significantly predicted SEPAQ scores, b = 10.95, t(113) = 6.63, p < .001. However, school sport participation did not significantly predict SEPAQ scores, b = 0.99, t(113) = 0.97, p > .05. Also, PAQ-A score and school sport participation explained a significant proportion of variance in SEPAQ scores, R^2= 0.33, F (2, 112) = 27.11, p < .001. Implications for male participation in physical activity are discussed.