Using a sample of 289 Iraq/Afghanistan veterans, this study examined the contributions of combat exposure, agency, perceived threat, and guilt to posttraumatic stress disorder (PTSD) symptoms. Regression analyses indicated the four variables (together with demographic variables) accounted for 79% of the variance in PTSD symptoms. Guilt was the most important predictor. In addition, guilt mediated between exposure and PTSD symptoms, perceived threat and PTSD symptoms, and agency and PTSD symptoms. Implications of these findings are discussed.