This study examined the effects of instructor support and students' global academic motivation on students' course-specific intrinsic motivation. The authors hypothesized, based on self-determination theory (Ryan & Deci, 2000), that instructor support for students' psychological needs would enhance intrinsic motivation. Students reported their global academic motivation as well as instructor support, perceptions of autonomy, competence and relatedness, and intrinsic motivation in a specific course. Instructor support predicted students' course-specific intrinsic motivation; effects were mediated by students' perceptions of autonomy and competence. Students' global intrinsic motivation directly affected their course-specific intrinsic motivation and had an indirect effect mediated by their perceptions of autonomy. Implications for college teaching are discussed. (Contains 2 figures and 2 tables.)