Military personnel who have experienced combat trauma are at risk for developing posttraumatic stress disorder (PTSD). A greater recognition of the complex array of vulnerability factors that contribute to PTSD severity has led researchers to examine other non–combat-related factors. This longitudinal study examined a number of pre-, peri-, and postdeployment factors hypothesized to contribute to PTSD symptomatology among returning Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn veterans presenting with at least subthreshold PTSD symptoms and hazardous alcohol use in a primary care setting. Purported risk factors included childhood family environment, severity of combat exposure, postdeployment social support, alcohol dependence severity, and an avoidant coping style. At baseline, postdeployment social support and avoidant coping contributed to PTSD severity. Only avoidant coping was associated with changes in PTSD symptom at 1-year follow-up. Reducing avoidant coping may deter the maintenance of PTSD among veterans with PTSD symptoms and hazardous alcohol use.