Concern with adolescent sex offenders is relatively recent. It appears to have begun in the early 1980's and to have grown dramatically since that time. Reasons for the increased concern and the resulting proliferation of studies are multiple. One of the most basic reasons is heightened awareness that the adolescent molester is a vital link in a chain of molestation in which younger children are damaged by older children and adolescents who have themselves been molested. The literature indicates adolescents are responsible for 20 percent of rapes in the United States and between 30 and 50 percent of all child sexual abuse. Victimization among adolescent sex offenders is estimated to range from 19 to 65 percent. Behavioral-cognitive and psychiatric models of adolescent sex offending are described, and typologies of adolescent sex offenders are presented. The author looks at sibling incest, the progression of adolescent sex offenses, strategic and tactical treatment effectiveness, and recidivism. Theoretical frameworks for understanding adolescent sex offenders are discussed, along with clinical observations of boys who molest, special groups of adolescent sex offenders, individual and family therapy, and countertransference issues. A level system to help male boys talk about their problems in the group setting is outlined in an appendix. References, tables, and figures