This article presents an analysis of social sustainability in comparative theoretical context and as a challenge to the post-political interpretation of sustainability in policy practice at the urban and regional scales. Metro Vancouver provides a case study for improving our understanding of the meaning of social sustainability as a framework for social policy in that it is among the handful of cities around the world currently working to define and enact social sustainability in governance terms. Results of this participant research provide evidence that some cities are politically engaging alternative development pathways using the concept of social sustainability. For sustainable development to retain its promise as an alternative policy framework for cities, social sustainability must be at the forefront.