Despite the apparent agreement today on the concept of sustainability, the means to achieve it holistically are still controversial. “Just sustainability” concept has recently gained traction, casting doubt on whether sustainability can be attained under capitalism. On the social level, many recent urban studies have been concerned with the concept of social justice and the distribution of resources and wealth as a means to achieving socially equitable sustainability. In this regard, a few questions are brought up: can social sustainability be achieved under capitalism? Are Islamic built environments a viable alternative? Many contemporary studies have described Islamic built environments as sustainable and strived for defining their sustainability criteria. However, they mostly focused on the built environment’s physical environmental aspects without relating them to the socio-economic spheres. Using the concepts of power and rights as key analytical tools, the paper examines a few capitalist utopian reform approaches and compares them in terms of their ability to achieve just sustainability with Islamic built environments. Several examples from primary Islamic history books will be used to examine Islamic built environments. It is concluded that Islamic built environments have attained the just sustainability that contemporary reform approaches sought to accomplish.