Widespread disparities in US healthcare have been documented with attendant speculation about their causes, including the potential role of the physician as a healthcare decision-maker. However, the current evidence on physician decision-making is inadequate to draw firm conclusions on how it relates to healthcare inequalities. In this article, we review the available evidence on physician decision-making as it relates to healthcare disparities, with an emphasis on its shortcomings, discuss potential sources of bias, including interpersonal factors and physician preferences, and make suggestions for further research in this area.