The purpose of this study was to examine the effects of a 12-wk. physical activity intervention, based on conceptual discussions and practices of a social cognitive theory on health-promoting behaviors of 62 university students. The intervention Mainly focused on development of self-regulatory skills, social support, and self-assessment of health-related fitness. The Adolescent Health Promotion Scale and International Physical Activity Questionnaire were given Analysis of self-reports indicated improved nutrition, health responsibility, social support, exercise, stress management, and overall health from pre- to postintervention. Also, participants' postintervention reports of moderate, vigorous, and total physical activity were higher than at preintervention.