The Penn State Worry Questionnaire for Children (PSWQ-C) is one of the most frequently used instruments to assess worry in children. The current study examines the measurement invariance of the PSWQ-C in a Romanian sample. Participants (n = 759) were recruited from both community and clinical populations. Our findings have replicated the good psychometric properties of the PSWQ-C and of the short PSWQ-C (the original scale with the negative items deleted). Multigroup confirmatory factor analysis has supported measurement invariance (configural, metric, scalar) across gender, age and clinical diagnosis. Convergent validity with other assessment measures has also been established. Finally, the implications of the use of the PSWQ-C in the assessment of anxiety in children and adolescents are discussed.