A review of related studies indicated that one of two contrasting hypotheses would be more correct than the other: either socioeconomic status determines both the IQ score and juvenile delinquent status or IQ alone is a determinant of delinquency. To test these hypotheses, analysis was performed on a study involving 36 boys with a schizophrenic parent, 36 with a psychopathic father or a character-disordered mother, and 57 whose parents had never been admitted to a psychiatric hospital. The boys were born between September 1959 and December 1961. The study reported on the relationship between 1972 measures of IQ (the Wechsler Intelligence Scale for Children) and socioeconomic status and registered delinquency assessed in 1978. When the effects of socioeconomic status were analyzed, verbal and full-scale IQ were shown to be related to delinquency. To cross-validate these findings, researchers repeated the analysis using a larger sample of 4,552 males born between January 1944 and December 1947. Again, IQ was found to be related to delinquency, independently of the effects of socioeconomic status. Thus, children who are characterized by a low verbal IQ may lack the abilities needed for securing rewards in school. The frustration and failure they experience may contribute to delinquency by creating a negative attitude toward authority, by inducing them to seek rewards in less socially desireable settings, or by making them more sensitive to the effects of delinquent peer pressure when peers provide an important source of esteem. However, IQ may only be related to some third variable that actually causes antisocial behavior. Data tables, footnotes, and a 34-item reference list are included.