Urban inequality has existed for as long as cities have existed, although the size, scale and form of inequalities will vary from time to time and place to place. Urban inequality has been a continuing concern for many social commentators, social scientists, politicians and policy makers. This chapter discusses key definitional issues with regard to urban inequality. It then goes on to reflect on its geographical scope, its forms and dimensions, including inequalities of resources, access and capabilities. It also covers underlying structural inequalities in terms of gender, race and ethnicity, and income and wealth. The chapter also analyses the role of the state and market in promoting or reducing inequality, including the impact of austerity policies.