The objective of this study was to assess the preliminary psychometric properties of the Reaction of Adolescents to Traumatic Stress questionnaire (RATS) for refugee adolescents. Four independent heterogeneous adolescent population samples (N = 3,535) of unaccompanied refugee minors, immigrants, and native Dutch and Belgian adolescents were assessed at school. The confirmatory factor analyses, per language version, support the three-factor structure of intrusion, avoidance/numbing, and hyperarsoual. The total and subscales of the RATS show good internal consistency and good (content, construct, and criterion) validity. The RATS, in this study, was found to be a reliable and valid instrument for assessing posttraumatic stress reactions of culturally diverse adolescents.