Recent proposals for revisions to the 11th edition of the International Classification of Diseases (ICD–11) posttraumatic stress disorder (PTSD) diagnostic criteria have argued that the current symptom constellation under the Diagnostic and Statistical Manual of Mental Disorders-5 is unwieldy and includes many symptoms that overlap with other disorders. The newly proposed criteria for the ICD–11 include only 6 symptoms. However, restricting the symptoms to those included in the ICD–11 has implications for PTSD diagnosis prevalence estimates, and it remains unclear whether these 6 symptoms are most strongly associated with a diagnosis of PTSD. Network analytic methods, which assume that psychiatric disorders are networks of interrelated symptoms, provide information regarding which symptoms are most central to a network. We estimated network models of PTSD in a national sample of veterans of the Iraq and Afghanistan wars. In the full sample, the most central symptoms were persistent negative emotional state, efforts to avoid external reminders, efforts to avoid thoughts or memories, inability to experience positive emotions, distressing dreams, and intrusive distressing thoughts or memories; that is, 3 of the 6 most central items to the network would be eliminated from the diagnosis under the current proposal for ICD–11. An empirically defined index summarizing the most central symptoms in the network performed comparably to an index reflecting the proposed ICD–11 PTSD criteria at identifying individuals with an independently assessed DSM–5 defined PTSD diagnosis. Our results highlight the symptoms most central to PTSD in this sample, which may inform future diagnostic systems and treatment.