Within this study, we investigated the association between 10th-grade students' mathematics performance and their feelings of instructional misalignment between their current mathematics knowledge and educator support. Data from the 2002 Education Longitudinal Study, which included a national sample of 750 public and private high schools in the United States, was used for the investigation. Our findings indicate that student perceptions of both instructional alignment and educator support are associated with mathematics performance. Students who reported receiving misaligned instruction in mathematics and felt devalued by educators had lower mathematics performance than students who reported aligned mathematics instruction and who felt valued by teachers. A key implication for practitioners of this work is that mathematics educators should consider cognitive and affective elements of student development. Specifically in addition to cognitive factors, the affective elements of student capacity to receive, respond to, and value whole-group mathematics instruction in academically diverse classrooms should be considered in curriculum planning. (Contains 1 table and 1 figure.)