This paper is based on research that demonstrates the positive effects of the cooperative learning model Group Investigation (GI) and the Six-Mirror model on teacher effectiveness in organizing and scaffolding CL activities, and changing students' and teachers' views of diversity. We explain how the connection between the two models leads to specific changes in the teachers' role and approach to implementing GI, which in turn lead to significant changes in students' and teachers' attitudes and points of view about cooperative learning and diversity, as revealed in teacher interviews.