The importance of reestablishing the link between urban planning and public health has been recognized in recent decades; this paper focuses on the relationship between urban planning/design and health equity, especially in cities in low and middle-income countries (LMICs). The physical urban environment can be shaped through various planning and design processes including urban planning, urban design, landscape architecture, infrastructure design, architecture, and transport planning. The resultant urban environment has important impacts on the health of the people who live and work there. Urban planning and design processes can also affect health equity through shaping the extent to which the physical urban environments of different parts of cities facilitate the availability of adequate housing and basic infrastructure, equitable access to the other benefits of urban life, a safe living environment, a healthy natural environment, food security and healthy nutrition, and an urban environment conducive to outdoor physical activity. A new research and action agenda for the urban environment and health equity in LMICs should consist of four main components. We need to better understand intra-urban health inequities in LMICs; we need to better understand how changes in the built environment in LMICs affect health equity; we need to explore ways of successfully planning, designing, and implementing improved health/health equity; and we need to develop evidence-based recommendations for healthy urban planning/design in LMICs.