We explored whether students' perceptions of emotional and instrumental support provided by their mathematics teacher constitute separate dimensions of teacher support and how they are related. We also analyzed how students' perceptions of emotional and instrumental support in math lessons relate to math anxiety, intrinsic motivation, help-seeking behavior, and effort. The participants were 309 Norwegian students in 9th and 10th grade. The data were analyzed by means of structural equation modeling (SEM). The results revealed that emotional and instrumental support constitute separate but strongly correlated constructs. Directly or indirectly, both emotional and instrumental support was related to all motivational constructs. The strongest relations were found for instrumental support. Additionally, instrumental support predicted lower levels of anxiety. One implication of this study is that teachers should aim at providing both emotional and instrumental support.