Social cognitive theory and the theories of reasoned action and planned behavior were examined in the prediction of 4 weeks of physical activity participation. The theories of reasoned action and planned behavior were supported. Attitude and perceived control predicted intention, and intention predicted physical activity participation. The social cognitive theory variables significantly predicted physical activity participation, with self-efficacy and self-evaluation of the behavior significantly contributing to the prediction. The greater the confidence in participating in physical activity and the greater the satisfaction with present physical activity, the more physical activity performed. Hierarchical regression analyses indicated that perceived control and intentions did not account for any unique variation in physical activity participation over self-efficacy. Therefore the social cognitive theory constructs were better predictors of physical activity than those from the theories of reasoned action and planned behavior.