The present investigation examined the role of teachers' instructional support (student reports of relevance, organization and clarity, feedback-feedforward) in predicting students' growth goal setting and, in turn, the roles of instructional support and growth goal setting in predicting students' academic engagement (perseverance, aspirations, school attendance, homework behavior). Also examined was the question of whether the relationship between students' background attributes and engagement is moderated by their growth goal setting (e.g., whether growth goal setting attenuates negative effects of low socioeconomic status). The sample comprised N = 61,879 students in grades 7-10 from schools across New South Wales, Australia. The results of structural equation modeling showed that perceived instructional relevance and feedback-feedforward from teachers positively predicted students' growth goal setting; that growth goal setting predicted gains in students' perseverance, aspirations, and homework behavior; and that growth goal setting significantly mediated the relationship between perceived instructional support and engagement. Additionally, growth goal setting appeared to significantly bolster some outcomes for low achieving students and students from low socioeconomic backgrounds. These findings add to the growing body of literature about the positive role of growth goal setting in students' outcomes and provide direction for educational practice.