Social anxiety disorder and social anxiety are highly prevalent psychological conditions in youth. Because of the known risks associated with the spectrum of social anxiety in youth, early detection with valid and reliable assessment measures is imperative. Self-report measures have become the most widely used method of assessment for child and adolescent social anxiety. Because research to date on self-report measures of social anxiety disorder in adolescents is limited, the primary objective of the present study was to contribute to the literature by examining the validity and reliability of a new self-report measure, the Social Phobia Inventory (SPIN), in a community sample of adolescents. The SPIN is a 17-item measure purported to assess the full spectrum of social anxiety disorder symptomatology. Previously, psychometric research on the SPIN in adult populations has demonstrated its validity and reliability. In the current psychometric examination, results revealed strong support for the temporal stability, internal consistency, and construct validity of the SPIN, suggesting it is an appropriate screening measure for the assessment of social anxiety disorder in adolescents.