Investigated the development and utility of the Negative Affectivity Self-Statement Questionnaire—Anxiety Scale (NASSQ-A) for youth. Participants in the initial anxiety-disordered (AD) sample were 68 children with a principal diagnosis of generalized anxiety disorder (GAD) or social phobia (SP), and participants in the non anxiety-disordered (NAD) sample were 37 children with no anxiety or mood disorder. Findings were then cross-validated on an additional sample of 138 children with a principal diagnosis of GAD or SP. Thirty-three negative self-statements were found to separate anxious from non-anxious participants, and were combined to form the NASSQ-A. Using Receiver Operating Characteristics (ROC) analyses, a NASSQ-A cutoff score of 49 was determined to be optimal for identifying anxiety-disordered youth. Findings are discussed with regard to the assessment of self-talk in anxiety disorders.