Studies have shown the United States faces a shortage of physicians, making it increasingly difficult for people to access needed health care. Physicians need graduate medical education (GME) training before they can practice medicine independently and often practice in the same geographic area as their training. The vast majority of federal funding for this training--about $15 billion in 2018--supports physician training through the Department of Health and Human Services' Medicare GME payments. Medicare offers payments to teaching hospitals to offset costs of training full-time equivalent residents, up to a capped number of resident slots for each hospital. The Government Accountability Office (GAO) was asked to review Medicare GME funding. This report describes the extent to which hospitals were over or under their Medicare GME caps and stakeholders' views on extending the time window before new caps are established. GAO analyzed 2018 Medicare data (the most recent available at the time of GAO's analysis), reviewed agency documentation, and interviewed eight selected stakeholder groups--including a GME accreditor and groups representing health care providers--identified through past GAO work.