There is now a considerable literature on the assessment and treatment of sexual offenders. There exists another substantial literature on therapeutic groupwork and its relevance to a range of clinical populations. These bodies of work have made reference to the other in terms of their mutual relevance. However, there has been no comprehensive attempt to apply groupwork theory and principles systematically to work with sex offenders. While this work is generally carried out using a group format and the application of groupwork principles is enthusiastically promoted in the field, the application is underdeveloped both empirically and even more so conceptually. As a result, practices vary greatly. We argue here that a systematic and integrated consideration of the application of groupwork methodology to the treatment of sex offenders has the potential to significantly enhance treatment effectiveness. We conclude with implications for training and clinical practice.