The psychometric properties of a questionnaire developed to assess symptoms of anxiety disorders (SCARED-71) were compared between two groups of children: children with high-functioning autism spectrum disorder and comorbid anxiety disorders (ASD-group; n = 115), and children with anxiety disorders (AD-group; n = 122). Anxiety disorders were established with a semi-structured interview (ADIS-C/P), using child- as well as parent-report. Internal consistency, construct validity, sensitivity, specificity, and discriminant validity of the SCARED-71 was investigated. Results revealed that the psychometric properties of the SCARED-71 for the ASD-group were quite comparable to the AD-group, however, the discriminant validity of the SCARED-71 child-report was less in the ASD-group. Raising the parental cutoffs of the SCARED-71 resulted in higher specificity rates, which suggests that research should focus more on establishing alternative cutoffs for the ASD-population.