The psychophysiology of posttraumatic stress disorder (PTSD) points towards autonomic dysregulation—specifically, elevated sympathetic response and attenuated parasympathetic response. In view of this, heart rate variability (HRV) biofeedback has been applied and tested as a treatment for PTSD. Review of existing published research suggests that HRV biofeedback seems promising as a treatment for PTSD, both in significantly alleviating the symptoms and in improving cognition for those suffering from PTSD. Drop-out rate is low, and inexpensive and portable HRV biofeedback devices such as the Stress Eraser make it a viable alternative to traditional treatment such as prolonged exposure therapy (PET), cognitive behavior therapy (CBT) and cognitive processing therapy (CPT). More recent research has also shown that combining HRV biofeedback with CBT, PET, and Acceptance and Commitment Therapy (ACT) improved the efficacy of these therapies in treating PTSD. More larger-scale and rigorous controlled trials are needed to confirm these outcomes.