Teachers have the largest school-based influence on student learning, yet there is little research on how instructional practice is systematically distributed within tracking systems. We examine whether teaching practice varies significantly across track levels and, if so, which aspects of instructional practice differ systematically. Using multilevel modeling, we find that teachers of low track classrooms provided significantly less emotional support, organizational support, and instructional support to students in their classes than did teachers of high track classrooms. Mathematics classes were also observed to have higher quality instructional support for both content understanding and analysis and problem solving than English classes. We develop cases illustrating how small but significant differences in instructional quality are associated with substantially diverging lived experiences for students in high and low track classes.