Objectives: The theory of planned behavior proposes that physical activity is the result of intentions; however little is known about whether the relation between intentions and behavior differs between vigorous, moderate physical activity, and walking. For university students, vigorous physical activity is oftentimes enacted as a goal-directed behavior; whereas walking is oftentimes a means to achieving a goal other than physical activity (e.g., transportation). Design: The study was a one-week prospective study. Methods: Undergraduate students (N = 164) reported intentions for walking, moderate physical activity, and vigorous physical activity and self-reported these behaviors one week later. Results: Hierarchical linear modeling revealed that intentions were more strongly related to vigorous physical activity than to moderate physical activity or walking. Conclusions: Intention-enhancing interventions may effectively promote vigorous physical activity, but other motivational processes may be more appropriate to targetin interventions of walking and moderate physical activity