Social anxiety disorder (SAD) is highly prevalent yet largely undetected and untreated in adolescents despite the availability of effective treatments. Implementing interventions in schools enhances recognition and access to treatment for SAD. However, without reliable means to accurately identify youth in need of services, school-based interventions are not feasible. The purpose of this study is to evaluate the utility of a two-step, school-based screening approach to identify youth with SAD. Students at three public high schools were screened with self-report questionnaires or nominated by school personnel. Subsequently, a brief telephone assessment of student symptoms was completed with students' parents. Results showed that using both questionnaires and telephone assessments yielded acceptable detection rates, while school staff nominations were not beneficial. This study provides support for the use of a two-step screening procedure consisting of student self-reports followed by brief parent telephone interviews to identify youth with clinically impairing social anxiety. Implications for enhancing school-based detection of and intervention for socially anxious adolescents are discussed.