Tracking is an instructional management practice in which students are assessed on achievement or intelligence and then assigned to differentiated curricula to match their abilities. The importance of tracking stems from its impact on student achievement and its broader implications for schools. Today, many countries throughout the world implement tracking in their schools. However, tracking is still viewed as a highly controversial practice because it is perceived as a source of educational inequality. In some cases, schools have actively sought to “detrack” their curricula by creating more heterogeneous classrooms. This entry provides a brief history of tracking, surveys leading perspectives on its advantages and disadvantages, and discusses the issues raised by detracking.