An adaptation of the Penn State Worry Questionnaire (Meyer, Miller, Metzger & Borkovec, 1990, Behaviour Research and Therapy, 28, 487–495) for use with children and adolescents was evaluated in two studies (Penn State Worry Questionnaire for Children: PSWQ-C). Study 1 involved the examination of factor structure, internal consistency, and convergent and discriminant validity in a school sample (N = 199). The measure was found to be unifactorial and to possess favorable reliability and validity. Study 2 evaluated the PSWQ-C in a clinical sample and found significantly higher scores in children with generalized anxiety disorder (n = 14) than children with other anxiety disorders (n = 10) and normal controls (n = 10). The PSWQ-C also demonstrated good convergent and discriminant validity and excellent reliability in the clinical sample.