This presentation will discuss the general foundations of family systems theory and review the literature that applies family systems theory to the treatment of sex offenders. We will then explore the various ways that family systems theory has influenced our sex offender treatment program at the University of Minnesotas Program of Human Sexuality, including the requirement that all spouses/partners attend a bi-monthly partner's group. We will highlight the lessons we have learned in our work with the partner's group, discussing both what has worked and what has not.