This chapter explores the role of a sustainable built environment in fostering circular economy principles within liveable cities. It highlights the importance of integrating sustainability into the urban infrastructure to create resilient, resource-efficient, and adaptable urban environments. With cities contributing significantly to global greenhouse gas emissions, there is a growing need to transition towards more circular models that prioritise reducing waste, reusing materials, and regenerating natural systems. The chapter discusses the key components of a sustainable built environment, such as energy-efficient construction, green architecture, and eco-friendly urban design. It emphasises how adopting circular economy principles in the built environment can help mitigate the environmental impact of cities by promoting resource conservation, reducing waste, and enhancing urban resilience. Furthermore, the chapter introduces regulatory, financial, and informational mechanisms that can support this transition, including emission-based taxes, pollution charges, and eco-certification programmes. By fostering innovation and collaboration between public and private sectors, cities can implement sustainable practices that balance economic growth with environmental stewardship. The chapter concludes by highlighting the importance of community engagement and public policy in shaping a sustainable built environment that contributes to the overall goal of creating liveable, circular cities.