Post-traumatic stress disorder (PTSD) continues to attract both empirical and clinical interest due to its complex symptom profile and the underlying processes involved. Recently, research attention has been focused on the types of memory processes involved in PTSD and hypothesized neurobiological processes. Complicating this exploration, and the treatment of PTSD, are underlying comorbid disorders, such as depression, anxiety, and substance use disorders. Treatment of PTSD has undergone further reviews with the introduction of eye movement desensitization and reprocessing (EMDR). EMDR has been empirically demonstrated to be as efficacious as other specific PTSD treatments, such as trauma-focused cognitive behavioral therapy. There is emerging evidence that there are different processes underlying these two types of trauma treatment and some evidence that EMDR might have an efficiency advantage. Current research and understanding regarding the processes of EMDR and the future direction of EMDR is presented.