Cross-lagged panel correlation technique is used to examine whether self-esteem has a greater effect on delinquency than delinquency has on self-esteem. Analysis of a nationwide study of tenth-grade boys shows that self-esteem is the more powerful causal factor, even when initial levels of delinquency are held constant. This result, however, is found to be stronger in the lower class than in the upper class. These data are interpreted as lending greater support to Kaplan's theory of the self-enhancing nature of delinquent behavior than to the idea of reflected appraisals.