This paper reviews the different treatment modalities used for treating sexual offenders. We provide an overview of the literature comparing group therapy with individual treatment and summarise the main advantages and disadvantages of both treatment modalities. Group treatment appears to be at least as effective as individual treatment, and there are several clinical advantages obtained through group processes which helpfully address the particular criminogenic needs of the sexual offender population and which are less easily obtained in individual therapy. In addition, we also address the debate about the advantages of open-ended versus closed-group formats. Openended groups seem to offer more clinical advantages than closed groups, and in particular allow for treatment to be more responsive to individual needs, although there have been no direct comparisons of the two approaches with sexual offenders. We conclude by identifying the next steps for research.