Clinician-rated measures are in extensive use as routine outcome measures in child and adolescent mental health services. We investigated cross-national differences and inter-rater reliability of the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA), the Children's Global Assessment Scale (CGAS) and the Global Assessment of Psychosocial Disability (GAPD). Thirty clinicians from 5 nations independently rated 20 written vignettes. The national groups afterwards established national consensus ratings. There were no cross-national differences in independent scores, but there were differences in national consensus scores, which were also more severe than independent scores. The ICC for the HoNOSCA total score was 0.84, for the CGAS 0.61 and for the GAPD 0.54. These measures may usefully contribute to cross-national comparison studies.