Although criminologists have long recognized the strong correlation between a persons delinquency and the delinquency of his or her friends, the mechanisms underlying this relationship remain elusive. The current study adds to research on peers and delinquency by exploring the behaviors of adolescents isolated from school friendship networks. Data from the National Longitudinal Study of Adolescent Health (Add Health) allow me to identify an isolated population and test theoretically derived hypotheses. Results suggest that low peer attachment in and of itself fails to increase future delinquency. However, isolation in conjunction with problematic peer encounters at school was found to significantly increase delinquency and delinquent peer associations. The theoretical implications of this interaction are discussed.