This study examined the psychometric properties of the Spence Children’s Anxiety Scale (SCAS) self-and parent-report versions in a community (n = 712) and a clinical (n = 70) sample of Brazilian children and adolescents. Confirmatory factor analysis conducted in the community sample provided support to the original six correlated factors model of the SCAS. Moreover, the SCAS demonstrated good internal consistency, convergent and divergent validity, and a significant informant effect on the total score with higher anxiety levels in the self-report than in the parent-report version. Considering the clinical sample, we could demonstrate that the SCAS total scores have good discriminant validity differentiating: (a) anxious, community, and negative screening groups; and (b) children diagnosed with different severity levels of anxiety disorders. Our findings suggest that the SCAS (self- and parent-report versions) is suitable for assessing anxiety symptoms in Brazilian children and adolescents in community and clinical settings.