Initial vaccine allocations for the coronavirus disease 2019 (COVID-19) will be limited. It is crucial to assess the ethical values associated with different methods of allocation, as well as important scientific and practical questions. This Viewpoint identifies three ethical values, benefiting people and limiting harm; prioritizing disadvantaged populations; and equal concern for all. It then explains why these values support prioritizing three groups: health care workers; other essential workers and people in high-transmission settings; and people with medical vulnerabilities associated with (...) poorer COVID-19 outcomes. In contrast, two other groups, people over 65 without medical vulnerabilities and participants in clinical research, present more complex ethical questions. This prioritization also encompasses valuing direct benefits to vaccinated individuals, indirect benefits to individuals protected from spread of infection, and indirect health and socioeconomic benefits to those protected from harm as health system and societal functioning improve. Vaccine allocation that recognizes important ethical values and avoids arbitrariness, waste, and corruption can ensure that the distribution of a COVID-19 vaccine is both fair and perceived as fair. (shrink)