AbstractThe authors examine the question of whether posttraumatic stress disorder (PTSD) should continue to be classified with the anxiety disorders in the upcoming revision of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‐V; American Psychiatric Association) classification system. They examine four areas of research that challenge the placement of PTSD among the anxiety disorders: research on peritraumatic emotions and their association with later PTSD symptoms, the role of emotions over the course of PTSD, physiological reactivity and emotional responses, and comorbidity patterns. The authors conclude with the recommendation that PTSD be included among a new category of traumatic stress disorders in DSM‐V.