The present study explored the direct influences of teacher classroom practices, including teacher support, conceptual teaching, and procedural teaching, on 9th grade students' mathematics achievement, and the indirect influences of these teacher variables on student mathematics achievement through students' mathematics self-efficacy and interest in mathematics courses. The base year data of High School Longitudinal Study of 2009 (HSLS: 09) was used for this study. Structural equation modeling method was used to estimate the relationships among variables. Results showed that teacher classroom practices influenced student mathematics achievement in different ways. Conceptual teaching positively, whereas procedural teaching negatively, influenced student mathematics achievement. Teacher support influenced student mathematics achievement indirectly through students' mathematics self-efficacy. It also had powerful influence on students' interest in mathematics courses. In addition, family socioeconomic status (SES) and student prior achievement were associated with teacher classroom practices. Students with higher levels of family SES and prior achievement were more likely to have teachers who use conceptual teaching strategies. Students with higher prior achievement were more likely to perceive higher levels of teacher support. / Ph. D.