It is urgent to make evidence-based treatments (EBTs) for military personnel readily accessible in order to meet the growing demand for effective and efficient treatment for posttraumatic stress disorder (PTSD) in a timely manner. Effective EBTs for PTSD are available, but barriers to accessing care can deter military personnel from receiving treatment. Web-treatments represent an innovative way to overcome these barriers. The efficacy of previously developed web-treatments for PTSD appear promising, however, they are not based on treatment protocols with strong empirical support for their efficacy. No study to date has examined web-treatment of PTSD using a well-established treatment program.

The purpose of this open trial is to examine the efficacy of 10 sessions of a web-version of Prolonged Exposure (PE), "Web-PE," delivered over 8-weeks in 40 active-duty military personnel and veterans with PTSD who deployed post 9-11. Up to 60 individuals will be consented to obtain data from 40 for analysis. Participants will be assessed at pre-treatment and 1- and 3-months after treatment completion.

Inclusion Criteria:

• Active-duty military personnel and veterans who have deployed post 9/11
• Seeking treatment for PTSD
• Significant PTSD symptoms as determined by a PCL-5 score greater than or equal to 31
• Has experienced a Criterion A event that is a specific combat-related event or high magnitude operational experience that occurred during a period of recent military deployment
• Able to speak and read English and access to an internet-connected computer
• Indication that the participant plans to be able to participant in the study for the next three months following the first assessment

Exclusion Criteria:

• Diagnosis of bipolar disorder or psychotic disorder, as determined by participant self-report)
• Current substance dependence, as determined by participant self-report)
• Diagnosis of a moderate or severe traumatic brain injury, as determined by participant self-report)
• Current suicidal ideation severe enough to warrant immediate attention, as determined by participant self-report)
• Currently engaged in evidence-based treatment for PTSD (e.g. Prolonged Exposure Therapy or Cognitive Processing Therapy), as determined by participant self-report.