This review compiles 48 empirical studies and 55 clinical/practice articles specific to group therapy with sex offenders. Historically, group therapy has always been the predominant modality in sex offender–specific treatment. In the first decades of the field, treatment applied a psychoanalytic methodology that, although not empirically supported, fully appreciated the primary therapeutic importance of the group modality. Conversely, since the early 1980s, treatment has applied a cognitive behavioral method, but the field has largely neglected the therapeutic value of the interpersonal group dynamics. The past decade has seen a growing re-appreciation of general therapeutic processes and more holistic approaches in sex offender treatment, and there is an emerging body of empirical research which, although often indirectly concerned with group, has yielded three definitive conclusions. First, the therapeutic qualities of the group therapist—specifically warmth, empathy, encouragement, and guidance—can strongly affect outcomes. Second, the quality of group cohesion can profoundly affect the effectiveness of treatment. Third, confrontational approaches in group therapy are ineffective, if not counter-therapeutic, and overwhelmingly rated as not helpful by sex offenders themselves. Additional conclusions are less strongly supported, but include compelling evidence that sex offenders generally prefer group therapy over individual therapy, that group therapy appears equally effective to individual therapy, and that mixing or separating groups by offense type is not important to therapeutic climate. Other group techniques and approaches specific to sexual abuse treatment are also summarized.