The main aim of this study was to analyze the factor structure and reliability of the Escala para la Ansiedad Social (EDAS) (Scale for Social Anxiety), a new self-report instrument developed to assess social anxiety in adolescence. The questionnaire was applied to a sample of 3181 high school students between the ages of 14 and 17. The scale consisted of 26 items and a 5-point rating-scale, from 1 to 5. The exploratory factor analysis isolated 2 factors: Social Anxiety and Interference, which accounted for 40.52% of variance. Internal consistency (.92) was high. No significant differences due to gender, age and gender by age were found, but females presented higher scores on the Social Anxiety subscale than males. Results support the reliability and validity of the EDAS in the assessment of social anxiety for Spanish adolescents.