This study explored the extent to which teachers' instrumental (i.e., tangible aid to promote learning) and appraisal support (i.e., teacher feedback) enhanced students' achievement in mathematics. Participants included 13,950 fifteen-year-old Canadian students who participated in the 2012 Programme for International Student Assessment. Based on students' reports, results from hierarchical regression analyses showed that instrumental support and teacher feedback respectively positively and negatively predicted math achievement. Further, teacher feedback made an additional contribution to math achievement over and above instrumental support. Findings suggest that different types of teacher support might differ in their efficacy in promoting math achievement.