Group psychotherapists commonly see feedback as one of the primary mechanism that furthers the goals of the group. This paper will summarize the research that has been done on the mechanisms leading members to produce feedback, the factors that induce members to accept feedback (for example, feedback valence and timing), and the effects of feedback on outcome and aspects of group process such as group cohesion. The article will address the practical implications of these findings for the interventions of the group psychotherapist. As will be discussed, the emphasis on the importance of feedback in the interpersonal group psychotherapy literature exceeds the programmatic research that has been done on basic questions. This paper will identify major lines of future investigation that could yield findings critical to the delivery of effective group psychotherapy such as the information processing sequences that underlie feedback delivery and reception.