In the United States alone, 19 million people suffer from depression, 100 million from chronic pain, and 40 million adults from anxiety (World Health Organization, 2012). In a country of roughly 320 million people, the effects extend beyond the millions of people struggling with mental disorders to also impact their families and friends. Finding an effective treatment or therapy plan is critical to improving the quality of life for these individuals. One approach that has shown varying levels of success is Acceptance and Commitment Therapy (ACT). To better understand is effectiveness, I will write a systematic review on the neurobiological underpinnings of ACT. I will compile papers relating to the psychological underpinnings of ACT, the physiological aspects of ACT, and changes in patients' neural pathways. The paper will explain how neural pathways may be altered through ACT, leading to a life with less pain and distress. I expect to find that ACT has roots in peaceful teachings and that it fosters physiological neural change.