Multicultural group work represents a powerful tool for helping and healing in the context of human diversity. This article summarizes multicultural group work, including task, psychoeducational, counseling, and psychotherapy groups, and describes a group work model for multicultural assessment, diagnosis, and treatment planning. Group work assessment and diagnosis should be culturally informed involving emic, etic, and a dialectic assessment perspective. Treatment planning begins with culturally informed conceptualizations of group treatment. It should include intentional stage-specific treatment strategies with multiculturally responsive interventions, which continuously address powerful inclinations, liabilities, and needs resulting from human diversity and dialectic interactions between diverse clients. (Contains 7 figures.)