The purpose of the present study was to explore the importance of perceived teacher affective support in relation to sense of belonging, academic enjoyment, academic hopelessness, academic self-efficacy, and academic effort in middle school mathematics classrooms. A self-report survey was administered to 317 seventh- and eighth-grade students in 5 public middle schools. Structural equation modeling indicated significant associations between perceived teacher affective support and middle school students' motivational, emotional, and behavioral outcomes. The structural model explained a significant proportion of variance in students' sense of belonging (42%), academic enjoyment (43%), self-efficacy beliefs (43%), academic hopelessness (18%), and academic effort (32%) in mathematics classrooms. In addition to providing the basis for a concise new measure of perceived teacher affective support, these findings point to the importance of students' perceptions of the affective climate within learning environments for promoting academic enjoyment, academic self-efficacy, and academic effort in mathematics. (Contains 2 figures and 3 tables.)