Physician supply refers to the number of trained physicians working in a health care system or active in the labor market. The supply depends primarily on the number of graduates of medical schools in a country or jurisdiction but also on the number continuing to practice medicine as a career path and remaining in their country of origin. The number of physicians needed in a given context depends on several different factors, including the demographics and epidemiology of the local population, the numbers and types of other health care practitioners working in the system, and the policies and goals in place of the health care system. If more physicians are trained than needed, supply exceeds demand. If too few physicians are trained and retained, some people may have difficulty accessing health care services. A physician shortage is a situation in which there are not enough physicians to treat all patients in need of medical care. That can be observed at the level of a given health care facility, a province/state, a country, or worldwide.

Health policy can be defined as the "decisions, plans, and actions that are undertaken to achieve specific healthcare goals within a society". According to the World Health Organization, an explicit health policy can achieve several things: it defines a vision for the future; it outlines priorities and the expected roles of different groups; and it builds consensus and informs people.