From a structuralist perspective, delinquent behavior is a consequence of social institutional practices, rather than of individual characteristics. The correlation of IQ with delinquency is not because IQ exerts any causal influence on delinquent behavior but because, in certain institutional settings (the schools), it may be selected by the institution as a criterion for differential treatment. Changes in institutional practices produce a change in the relationship between IQ and delinquency. Empirically, the variables in the structuralist model developed by the Office of Youth Development explain over 20 percent of the variance in serious and nonserious delinquency. The variables used in the IQ-delinquency hypothesis, a model based on individual characteristics instead of on institutional practices, explain less than 5 percent of the variation in serious and nonserious delinquent behavior. The article concludes that the IQ-delinquency hypothesis contributes nothing to existing delinquency theory. Figures, tables, footnotes, and over 50 references are included. (Author abstract modified)