In this study, the authors examine the influence of teacher and student communication patterns, instructional practices, and teacher pedagogical content knowledge on students' mathematics learning in both general and special education mathematics classrooms. Five pre-service special education teachers and 43 students with varying disabilities participated in this study. Results reveal two sets of instructional practices, communication patterns, and teacher understandings of mathematics for teaching that differentially affected student performance. Implications are discussed for teacher education and further research.