Objective: Social phobia typically develops during the adolescent years, yet no nationally representative studies in the United States have examined the rates and features of this condition among youth in this age range. The objectives of this investigation were to: (1) present the lifetime prevalence, sociodemographic and clinical correlates, and comorbidity of social phobia in a large, nationally representative sample of U.S. adolescents; and (2) examine differences in the rates and features of social phobia across the proposed "DSM-5" social phobia subtypes. Method: The National Comorbidity Survey Replication-Adolescent Supplement is a nationally representative face-to-face survey of 10,123 adolescents 13 to 18 years of age in the continental United States. Results: Approximately 9% of adolescents met criteria for any social phobia in their lifetime. Of these adolescents, 55.8% were affected with the generalized subtype and 44.2% exhibited nongeneralized social phobia. Only 0.7% met criteria for the proposed DSM-5 performance-only subtype. Generalized social phobia was more common among female adolescents and risk for this subtype increased with age. Adolescents with generalized social phobia also had a younger age of onset, higher levels of disability and clinical severity, and a greater degree of comorbidity relative to adolescents with nongeneralized forms of the disorder. Conclusions: This study indicates that social phobia is a highly prevalent, persistent, and impairing psychiatric disorder among adolescent youth. Results of this study also provide evidence for the clinical utility of the generalized subtype and highlight the importance of considering the heterogeneity of social phobia in this age group. (Contains 1 figure and 3 tables.)