Findings from recent studies indicate that the use of afterschool tutoring is not unique to East Asia and may have become more popular across countries and over time. As after-school tutoring becomes more popular worldwide, it raises concerns over the distribution of student performance. Three key concerns addressed in this study are (a) whether the use of after-school tutoring promotes student performance, (b) whether students perform more unequally as after-school tutoring becomes more widely practiced, and (c) whether students of certain ability levels benefit more from after-school tutoring than do others. Findings of this study show that participating in either mathematics or science tutoring after school is found to raise national average performance without widening the dispersion in student performance. In science, lowperforming students benefit more from tutoring than do high-performing students. In mathematics, however, highperforming students benefit more from tutoring than do low-performing students.