LAUSR

Abstract In the U.S., graduate student instructors teach a substantial percentage of undergraduate courses. Teaching motivation is an important predictor of high-quality teaching; thus, understanding the motivations and beliefs of graduate student instructors is essential for undergraduate student success. Graduate students also form the pool from which faculty members are selected, so the trajectories of emerging faculty are often set during these formative teaching experiences. Our study explored antecedents of teaching self-efficacy for 98 graduate student instructors from STEM, humanities, and social science disciplines. We found that the number of semesters completed in graduate school and being in a non-STEM field were positively associated with teaching self-efficacy for instructional approaches and teaching self-efficacy for learning environment, respectively. Additionally, we found that teaching self-efficacy along with autonomy-supportive instruction was positively related to undergraduates’ classroom engagement (n = 2623). Relations between perceptions of autonomy-support and classroom engagement were moderated by teaching self-efficacy; this moderation was more pronounced for STEM contexts. Implications for research and practice are discussed.