Justice is a context-dependent, multi-faceted concept that has historically been associated with planning theory. In this paper, the literature surrounding the concept of justice will be explored to understand where the concept of justice has come from, how it has evolved, and how it can be applied to the planning process. In addition, how justice interacts with other critical concepts, such as the law, morality, and ethics, as well as its ability to function within the institutional context will also be assessed. The concept of justice is be applied to the planning process as it occurs in planning practice in an attempt to bridge the theory-practice gap that exists in planning. Using Fainstein’s concept of justice, with her three criteria of equity, diversity, and democracy, the planning process of the two redevelopments of Regent Park is assessed through the lens of justice in an attempt to apply theories of justice to planning practice.