The present paper reviews what is currently known about sexual abuse and the treatment of the offenders. Sexual offending is primarily committed by males and as many as 50% of females and 33% of males are sexually victimized in some way during their life. While some of these acts involve minimally intrusive behaviours (e.g. exhibitionists), many involve forced vaginal or anal intercourse and varying degrees of associated physical violence and deliberate humiliation of the victim. The effects on the victim can be severe and long-lasting. Current theories of the aetiology of these behaviours incorporate biological and developmental factors occurring within a socio-cultural context that fails to discourage sexual abuse. Experience is said to create a vulnerability that in some men finds expression in sexually abusive behaviour. Appropriate assessment targets the issues that are addressed in treatment, including: cognitive distortions, sexual behaviours and attitudes, social functioning and substance abuse. In addition, treatment also attempts to generate a set of relapse prevention plans for each offender. While some reports have not found benefits for treatment, the majority of acceptable studies have demonstrated clear reductions in re-offending among treated sexual offenders.