r Cities, which are where the majority of the world's population lives today, directly and indirectly shape human health and well-being.r Urban health research, policy, and practice are increasingly using a systems science approach to address the upstream and downstream drivers of health in cities, which include social and environmental factors, features of the built environment, conditions of living, and health care resources.r To guide future scholarship and policy, we propose an urban health agenda for 2050 focused on revitalizing the sanitation movement, integrating data, scaling best practices, adopting the Health in All Policies approach, and addressing intraurban health inequities.