This study looked at the influence of a Sport Education intervention program on students' motivational responses in a high school physical education setting. Two intact groups were assigned curricular interventions: the Sport Education group (n = 25), which received eight 60-min lessons, and the comparison group (n = 26), which received a traditional teaching approach to sport-based activity. Pre- and postintervention measures of student enjoyment, perceived effort, perceived competence, goal orientations, perceived motivational climate, and perceived autonomy were obtained for both groups. Repeated-measures ANOVAs showed significant increases in student enjoyment and perceived effort in the Sport Education group only. Hierarchical regression analyses revealed that increases in task-involving climate and perceived autonomy explained a significant amount of unique variance in the Sport Education students' postintervention enjoyment, perceived effort, and perceived competence responses. The results suggest that the Sport Education curriculum may increase perceptions of a task-involving climate and perceived autonomy, and in so doing, enhance the motivation of high school students toward physical education.