["Journal of Traumatic Stress, EarlyView. ", "\nAbstract\nThis study examined whether DSM‐5 and ICD‐11 self‐report operationalizations of posttraumatic stress disorder (PTSD) are psychometrically equivalent. Using Rasch modeling, we compared the psychometric properties and convergent validity of the PTSD Checklist for DSM‐5 (PCL‐5) and the International Trauma Questionnaire (ITQ) in a sample of 483 Syrian refugees residing in Türkiye (63.9% women, Mage = 31.60 years, SD = 11.48). Both instruments demonstrated acceptable model fit and reliability. However, the PCL‐5, r = .792, showed significantly stronger associations with depression than the ITQ, r = .691, p < .001, whereas associations with anxiety were comparable. Probable PTSD prevalence was higher using DSM‐5 criteria (26.9%) than ICD‐11 criteria (21.9%). A proxy score comprising PCL‐5 items mapped onto ICD‐11 symptom clusters also correlated more strongly, r = .790, withdepression than the ITQ, r = .701, suggesting that differences in item content rather than item count drive the observed pattern. These findings indicate that the PCL‐5 and ITQ are not psychometrically equivalent. The PCL‐5 appears to capture a broader internalizing distress syndrome, whereas the ITQ provides a more parsimonious assessment of trauma‐specific symptoms. The results are specific to self‐report operationalizations and cannot be generalized to clinician‐administered diagnoses. The choice of assessment instrument may, therefore, meaningfully influence prevalence estimates, comorbidity patterns, and the interpretation of PTSD in trauma‐exposed populations.\n"]