Multiple research studies have been conducted that focus on various uses of collaborative learning in and out of the classroom in higher education institutions. The purpose of this article is to review previously published literature regarding group composition and how it affects student interaction and achievement. Group composition research has been focused on gender, ethnicity, member familiarity, ability level, as well as motivational level and source. Examples of student achievement often include test scores, grade point averages, and opinion-based surveys on group collaboration. Group composition is always associated with the effects of multiple confounding variables due to the overall nature of collaborative learning at the college level. (Contains 1 table.)