Abstract: Despite the onset of an economic recession, Australia’s cities continue to grow, presenting challenges to urban and regional planners who must consider how best to redevelop outdated urban infrastructure and establish new infrastructure to meet the needs of increasing urban populations. The degree to which policy makers and planners can steer new and existing developments towards sustainability is affected by how decision makers understand sustainability. This paper discusses the social dimensions of urban sustainability and measurement issues. It draws on work in progress on a broader project to develop a model to assess triple bottom line sustainability in urban infrastructure development. It is argued that the concept of social sustainability has categories that are synergetic but there also inherent tensions. The form of the built environment affects the opportunities available for social relationships to form but this perspective seems to not fully address how humans might interact in complex ways with social structures with implications for understanding social sustainability