Posttraumatic Stress Disorder (PTSD) is an often chronic and disabling condition prevalent in the Veteran population. Many effective treatments, such as medications and psychotherapy, for PTSD have been developed and deployed in the VA. Other more procedural or “somatic” treatments appear promising but are understudied. One such understudied somatic treatment is repetitive transcranial magnetic stimulation (TMS). TMS has shown clear efficacy in the treatment of depression, and the U.S. Food and Drug Administration has approved TMS for this indication. Beyond this, early studies indicate that TMS is a highly promising somatic therapy for PTSD. While functional improvement and recovery are central goals for PTSD treatment, the majority of PTSD treatment studies do not include measures of functional improvement. Moreover, none of the TMS treatment studies in PTSD have examined functional outcomes. Therefore, research is needed to determine: (1) if TMS is an effective treatment for PTSD; and (2) if TMS is associated with functional improvement. The immediate objective of this study is to determine whether TMS is an effective treatment for PTSD. We will also compare the efficacy and functional improvement associated with treatment. The long-term goal is to improve the health of Veterans with PTSD through development of effective treatments. We seek to study several interrelated research questions. First, is transcranial magnetic stimulation delivered to the right dorsolateral prefrontal cortex of Veterans with PTSD more effective in decreasing symptoms of PTSD compared to sham treatments? Second, does transcranial magnetic stimulation delivered to the right dorsolateral prefrontal cortex effective for improving functioning Veterans with PTSD? We propose a four-year study to answer these questions regarding the use of TMS for the treatment of PTSD. During the study, 91 participants from the White River Junction VA Medical Center will be randomized to either TMS or sham TMS; all TMS will be applied to the right dorsolateral prefrontal cortex. All participants will meet DSM-V criteria for PTSD. The primary outcome will be change in severity of PTSD symptoms as measured as a continuous variable using the Clinician Administered PTSD Scale (CAPS). Secondary outcomes include function, depressive symptoms, and side effects.