For over a century, undergraduate medical education (UME) has adhered to the “two-pillar” model focused mainly on the basic and clinical sciences. As a result, newly graduated medical students often state a lack of understanding of the structure and function of the U.S. health care delivery system. To bridge this gap, in 2016 the American Medical Association’s Accelerating Change in Medical Education Consortium introduced a new “third-pillar” of UME called Health Systems Science (HSS). HSS focuses on the broader context of health care delivery including organizational structures and processes, policy, economics and management, clinical informatics and health information technology, population health, value-based care, and health system improvement.