Social discounting refers to the fact that most people assign more value to the welfare of close affiliates than they do to the welfare of distant affiliates—they discount the latter compared to the former. We report the first study to apply a social discounting paradigm to boys. We were particularly interested in investigating the relations between social discounting, age, and externalizing behavior problems (antisocial behavior). Results showed that (1) preadolescent boys were more likely than adolescent boys to show atypical response patterns in allocating rewards to affiliates; (2) task behavior was well represented as social discounting once boys with atypical response patterns were deleted from the sample, and (3) boys functioning in the clinical range on indices of externalizing behavior problems demonstrated steeper social discounting compared to controls. We conclude that social discounting as a measure of perceived social closeness is feasible for use in adolescent samples. Social discounting may operate similarly to other forms of discounting in impulsive individuals. Copyright © 2011 John Wiley & Sons, Ltd.