BackgroundSuicide is a leading cause of death worldwide, with childhood maltreatment identified as a significant risk factor for suicidal behavior in adulthood. The link between childhood maltreatment and suicidality is well-documented; however, the role of complex posttraumatic stress disorder (CPTSD), which includes an additional symptom cluster of disturbances in self-organization (DSO) compared to posttraumatic stress disorder (PTSD), remains underexplored. This study aimed to investigate the association between meeting the criteria for ICD-11 PTSD or CPTSD and suicidality in adults with a history of childhood maltreatment across culturally diverse samples. MethodsData were collected across four sites: the United States, the United Kingdom, China, and Malaysia. The Childhood Trauma Questionnaire (CTQ), Suicidal Behaviors Questionnaire-Revised (SBQ-R), and International Trauma Questionnaire (ITQ) were used to assess childhood maltreatment, suicidality, and PTSD or CPTSD, respectively. Linear regressions were conducted to examine the associations, controlling for demographic variables (age, sex, ethnicity, educational level, and subjective socioeconomic status) as well as the severity of maltreatment (CTQ total scores). ResultsAmong the 1,324 participants who experienced childhood maltreatment, meeting the criteria for CPTSD was significantly associated with higher suicidality compared to not meeting the criteria for either PTSD or CPTSD (B(SE) = 1.68 (0.30), p < .001), or only meeting the criteria for PTSD (B(SE) = 1.38 (0.43), p < .001). In contrast, meeting the criteria for PTSD alone was not significantly associated with suicidality (B(SE) = 0.35 (0.46), p = .45). These associations remained consistent across different cultural settings. ConclusionThe study findings highlight the unique association of CPTSD with suicidality in adults with a history of childhood maltreatment, suggesting that the DSO symptom cluster of CPTSD, which distinguish it from PTSD, play a critical role in the development of suicidality in this population. Targeting these symptoms may be essential for effective intervention strategies. Screening for childhood maltreatment and CPTSD in individuals at risk of suicide is crucial for guiding treatment planning.