We examined the association between changes in the substances and mediating variables targeted by the All Stars drug prevention curriculum, and students' engagement in and enjoyment of the curriculum, their attitudes toward their teachers, and their perceptions of their teachers' skills. Forty-eight school staff administered at least one All Stars class, for up to three consecutive years, to their seventh grade students in 107 classes in a large Midwestern school district. A sample of 2428 students completed a linked pretest and post-test, for a response rate of 91%. We found that students' engagement in and enjoyment of the curriculum, their attitudes toward their teachers, and their perceptions of their teachers' skill were all associated with positive changes in the curriculum's five mediators, but not with changes in students' substance use per se. Study findings suggest the importance of these three attributes to the achievement of the objectives of prevention curricula. (Contains 4 tables.)