The aim of this study was to test the cognitive content-specificity hypothesis in children and adolescents aged 7-16 years. Participants consisted of a community sample of 200 youth and a clinical sample of 160 youth with anxiety, depressive, or disruptive behavior disorders. Participants completed several self-report measures assessing a wide range of negative beliefs and symptoms of internalizing and externalizing problems. Multivariate analyses examining the interrelationships between beliefs and noncognitive symptoms revealed that thoughts on loss or personal failure were the strongest predictors of depressive symptoms, thoughts on social threat were the strongest predictors of anxiety symptoms, and thoughts on hostility or revenge were the strongest predictors of aggression. Results showed clear evidence of cognitive-affective specificity across both internalizing and externalizing problems in youth.