Sexual aggression by children is a complex phenomenon. The younger a child is at the onset of sexually aggressive behavior the more likely that sexual victimization occurred. Sexualized aggressive behaviors exhibited by children frequently constitute a reliable marker for sexual abuse victimization if the sexual behaviors are developmentally inappropriate, frequent, chronic, and persistent. There are five criteria for the identification of sexual reactivity: (1) the repetitiveness of the sexually aggressive acts; (2) the unresponsiveness to adult intervention; (3) the criminal nature of the behavior if it were committed by an adult; (4) the occurrence of the behavior across time and situation; and (5) the variety and sophistication of the sexual acts exhibited. Male children display more sexually aggressive behaviors than female children. Sexual behaviors of sexually aggressive children (SAC) are anomalous based on their deviance from expected psychosexual development stage parameters, are compulsive and resistant to change, and lack the inhibition normally associated with latency. Deviant sexual behaviors are motivated by bullying, coercion, and the re-enactment of past sexual trauma. It is usual for SAC to threaten, bribe, or use guilt to prevent disclosure of the abuse by the victims. Estimates vary about the number of SAC who may be diagnosed with psychiatric disorders. They suffer from low self-esteem, feelings of inadequacy, vulnerability, and sexual abuse victimization. They are at high risk for peer rejection and academic failure. Sexual abuse is associated with greater levels of familial distress and fewer educational and financial resources in the family. The most commonly espoused theoretical orientation to treatment is cognitive-behavioral, as well as developmental and family systems perspectives. SAC treatment must address the separation of sexual arousal from negative situations and effects. The treatment must include the family. Social, communication, and interpersonal problem-solving skill development may be necessary to counteract social isolation and peer marginalization. 1 table, 56 references