Objective: There is little evidence that posttraumatic stress disorder (PTSD) is more likely to follow traumatic events defined by Criterion A than non–Criterion A stressors. Criterion A events might have greater predictive validity for International Classification of Diseases (ICD)-11 PTSD, which is a condition more narrowly defined by core features. We evaluated the impact of using Criterion A, an expanded trauma definition in line with ICD-11 guidelines, and no exposure criterion on rates of ICD-11 PTSD and Complex PTSD (CPTSD). We also assessed whether 5 psychologically threatening events included in the expanded definition were as strongly associated with PTSD and CPTSD as standard Criterion A events. Method: A nationally representative sample from Ireland (N = 1,020) completed self-report measures. Results: Most participants were trauma-exposed based on Criterion A (82%) and the expanded (88%) criterion. When no exposure criterion was used, 13.7% met diagnostic requirements for PTSD or CPTSD, 13.2% when the expanded criterion was used, and 13.2% when Criterion A was used. The 5 psychologically threatening events were as strongly associated with PTSD and CPTSD as the Criterion A events. In a multivariate analysis, only the psychologically threatening events were significantly associated with PTSD (stalking) and CPTSD (bullying, emotional abuse, and neglect). Conclusions: Certain non–Criterion A events involving extreme fear and horror should be considered traumatic. The ICD-11 approach of providing clinical guidance rather than a formal definition offers a viable solution to some of the problems associated with the current and previous attempts to define traumatic exposure.