We assessed the delay of gratification behavior of 428 twelve and thirteen-year-old boys, half of whom were known to manifest symptoms of behavioral disturbance. Consistent with the hypothesis that low self-control is a risk factor specific to externalizing (aggressive and delinquent) disorders, boys who showed signs of externalizing disorders tended to seek immediate gratification in a laboratory task more often than both nondisordered boys and boys who showed signs of internalizing (anxious and depressed) disorders. In addition, children who were able to delay immediate gratification were described by their mothers as ego controlled, ego resilient, conscientious, open to experience, and agreeable. These results suggest that poor delay of gratification may be one of a select number of specific risk factors for externalizing