The current study examined the relative impact of school and classroom goal structures on students' affective responses and the mediating role of motivation. The sample of the study consisted of 368 high school students, who completed measures of school and classroom goal structures, motivational regulations in physical education, boredom, and enjoyment. The results of the study indicated that school goal structures significantly predict the respective classroom structures. When tested simultaneously, classroom goal structures had stronger ability in predicting affective outcomes compared to school structures. Mastery goal structures predicted enjoyment, whereas performance goal structures boredom. Furthermore, autonomous forms of motivation predicted enjoyment, whereas less autonomous forms boredom. The findings of the present study suggest that physical education teachers should promote a mastery-oriented motivational climate to foster students' positive affective responses. (Contains 3 tables.)