Few North American institutional or community female sex offender programs use standardized assessments, so the only typological schemes have emerged from unstructured clinical observation. The typologies that do exist are based on small samples of mostly adjudicated adults. This article identifies three typologies of female sex offenders. One is the teacher/lover sex offender, who initiates the sexual abuse of an adolescent from a position of power obtained through either age or status as mother, aunt, or guardian. A second type is the male-coerced sex offender, who is induced or forced into sexual abuse by a male, usually of their daughters. A third typology, predisposed sex offenders, usually victimize their own children, without male accomplices. It is difficult to group female sex offenders by their mental health problems because of the variety of assessment procedures and criteria across studies. Some researchers, have, however, found a higher incidence of schizophrenia and developmental delay among female sex offenders than among male sex offenders. A small minority of teacher/lover and male-coerced sex offenders are developmentally delayed. Effective treatment of the female sex offender depends on the accuracy of the match between the chosen intervention and the specific needs of the offender. It is important not to overlook issues such as substance abuse, dissociation, self-injury, and inappropriate sexual attitudes that may arise from victimization experiences. 18 footnotes