Introduction: Rates of torture are especially high among those seeking asylum, with global estimates of forced migrants having experienced torture exceeding 50%. Torture is the strongest predictor of PTSD amongst refugee populations. This study assesses the construct validity and diagnostic rate of the ICD-11 PTSD and Complex PTSD (CPTSD) within a population of torture survivors seeking asylum in Ireland. It further explores whether this population were more likely to meet the diagnostic criteria for CPTSD than PTSD, and whether any sex differences existed in probable rates of PTSD and CPTSD. Methods: A secondary data analysis of 264 treatment-seeking asylum seekers and refugees who experienced torture or ill-treatment was conducted. Rates of PTSD and CPTSD were assessed using the International Trauma Questionnaire. Findings: A Confirmatory Factor Analysis supported a a six-factor correlated model consisting of re-experiencing (Re), avoidance (Av), threat (Th), affective dysregulation (AD), negative self-concept (NSC), and disturbed relationships (DR), consistent with ICD-11 PTSD and CPTSD. High rates of PTSD (32.4%) and CPTSD (39.6%) were found, with the experience of torture significantly associated to the development of PTSD. No significant difference was found between the sexes. Discussion: This is the first study to investigate the validity of ICD 11 PTSD and CPTSD among torture survivors actively seeking international protection in Europe. Given the high rates of PTSD and CPTSD found among torture survivors, rehabilitation centres for victims of torture should consider CPTSD as part of their assessment and treatment programmes.