The International Grief Questionnaire (IGQ) is a self-report measure of ICD-11 Prolonged Grief Disorder (PGD) in adults. This study sought to develop and validate a caregiver-report version of the IGQ for children and adolescents aged 7-17 years; the IGQ-Caregiver Version (IGQ-CG). 639 parents living in Ukraine provided data on themselves and one child in their household as part of the " study. The latent structure of the scale was tested using confirmatory factor analysis (CFA), while convergent validity was assessed through associations with other mental health correlates. Prevalence rates of probable ICD-11 PGD were estimated. CFA results supported a correlated two-factor model ('core' and 'associated' symptoms) and the internal reliability of the scale scores were acceptable. Convergent validity was supported through significant correlations with internalizing symptoms, while contact with the deceased, time since bereavement, and parental PGD were associated with higher scores on the IGQ-CG latent variables. The prevalence of probable ICD-11 PGD was 1.4%, and amongst those with a lifetime bereavement, the conditional rate was 3.2%. The IGQ-CG produces reliable and valid scores for ICD-11 PGD symptoms in children and adolescents as reported by their caregivers.