Objective: Support for ICD-11 post-traumatic stress disorder (PTSD) and complex PTSD (CPTSD) is growing; however, few studies include refugees or examine the clinical utility of PTSD/CPTSD classifications. This study sought to provide the first evaluations of (i) the factor structure of ICD-11 PTSD/CPTSD amongst refugees in the Middle East; and (ii) the clinical utility of the International Trauma Questionnaire (ITQ) to identify PTSD/CPTSD in a humanitarian context. Method: Participants were 112 treatment-seeking Syrian refugees living in Lebanon. Factorial validity was assessed using confirmatory factor analysis (CFA) based on responses to the ITQ. Clinical utility of the ITQ was assessed through semi-structured interviews with six Lebanese psychotherapists. Results: Complex PTSD (36.1%) was more common than PTSD (25.2%), and no sex or age differences were observed at the prevalence or symptomatic levels. CFA results supported a two-factor higher-order model consistent with ICD-11 PTSD/CPTSD. Qualitative findings indicated that the ITQ is generally positively regarded, with some limitations and suggested modifications noted. Conclusion: This is the first study to support the ICD-11 PTSD/CPTSD amongst refugees in the Middle East and the clinical utility of the ITQ in a humanitarian context. Findings support the growing evidence for the cross-cultural applicability of ICD-11 PTSD/CPTSD.