Changing market forces increasingly are leading academic medical centers (AMCs) to form or join health systems. But it is unclear how this shift is affecting the tripartite academic mission of education, research, and high-quality patient care. To explore this topic, the authors identified and characterized the types of health systems that owned or managed AMCs in the United States in 2016 using the Agency for Healthcare Research and Quality 2016 Compendium of U.S. Health Systems. The findings suggest that several distinct types of relationships between academic-affiliated health systems (AHSs) and medical schools exist. The traditional vision of a medical school having an exclusive relationship with a single AHS is no longer prominent.