A review of the literature on the relationship between ability grouping and student achievement reveals that most researchers have found that homogeneous grouping does not significantly affect achievement. A few studies attempted to relate student achievement to teacher ability and instructional strategies; however, they found no significant relationship between the variables. A very limited number of studies tried to assess the relationship of heterogeneous grouping and student achievement. These studies found a significant increase in student achievement in classes in which the heterogeneous groups were also high-aptitude groups. The research in this area has been limited and suggests that more studies ought to be done to investigate the effects of heterogeneous grouping and how student achievement is affected by class aptitude. (RH)