The Flexner Report highlighted the importance of teaching medical students to reason about uncertainty. The science of medical decision making seeks to explain how medical judgments and decisions ought ideally to be made, how they are actually made in practice, and how they can be improved, given the constraints of medical practice. The field considers both clinical decisions by or for individual patients and societal decisions designed to benefit the public. Despite the relevance of decision making to medical practice, it currently receives little formal attention in the U.S. medical school curriculum. This article suggests three roles for medical decision making in medical education. First, basic decision science would be a valuable prerequisite to medical training. Second, several decision-related competencies would be important outcomes of medical education; these include the physician's own decision skills, the ability to guide patients in shared decisions, and knowledge of health policy decisions at the societal level. Finally, decision making could serve as a unifying principle in the design of the medical curriculum, integrating other curricular content around the need to create physicians who are competent and caring decision makers.