The health status of an older person is the result of many factors, including lifelong health habits, genetics, and exposure to occupational and environmental hazards. The quality and availability of health care throughout the life course also plays a significant role in health in later life. These social determinants—the circumstances of our lives, including the neighborhoods in which we live—affect health risks and outcomes over the life course. Individual health behaviors are affected by the practices and habits of the people in one’s immediate social world, but they are also determined by the social circumstances of one’s life. This chapter explores the broad range of individual behaviors and social determinants that shape health in later life. It also examines the policies and practices within the U.S. health care system that shape access to and quality of health care for older adults.