This research focuses on the role social equity has played in sustainable development since the 1990s using the inclusion of affordable housing as a metric. Through the collection and examination of 492 sustainable and smart growth, mixed-use developments it was identified that less than 40 percent included affordable housing. While this suggests that some progress has been made in the efforts to address social equity in development, it also indicates a significant disparity in the intended beneficiaries of sustainable development. Economic sustainability has been a given since the birth of capitalism. Environmental sustainability entered popular literature in the middle to late 1900s as the effects of environmental pollution and urban sprawl began to be noticed and drew considerable concern. Since the 1990s social sustainability, particularly in the forms of distributive justice and social equity.