There is extensive research examining the attachment styles of men who sexually offend. The results indicate that this population often has insecure attachment styles with significant deficits in their attachment behaviors. It has been theorized that such deficits are influential factors in both the etiology and maintenance of sexually offending behaviors. This article first describes attachment theory and then explains how it is related to the development of human sexuality. Next, empirical research examining the relationship between attachment and men who sexually offend is reviewed. Finally, a description and the possible benefits of an attachment theory informed approach to the treatment of adult men who sexually offend are discussed.