Ethnicity and culture have great therapeutic import in the practice of group psychotherapy, especially given the increasing diversify of the population of North America, and this issue has not received appropriate recognition in the literature. In this paper these terms are defined, and the literature is reviewed. Ethnicity, culture, and psychopathology are discussed, focusing on treatment issues including transference, countertransference, resistance, group cohesion, group process, and multi-ethnic groups. The group therapist must be knowledgeable about ethnic and cultural issues in the lives of the group members in order to promote group cohesion and therapeutic effectiveness. The recognition and exploration of ethnic/cultural differences enhances the work of the group. Recommendations for treatment are discussed.