As global energyGlobal energy demand rises alongside rapid urbanization, the need for sustainable urban development becomes increasingly critical. This chapter explores the concept of eco-citiesEco-cities, focusing on sustainable practices that integrate renewable energy, zero-waste management, and water conservation. It also examines the role of innovative urban planning in mitigating the environmental impacts of mass urbanizationMass urbanization. Eco-citiesEco-cities prioritize resilience, circular economies, and carbon–neutral development, addressing the urgent need to decouple economic growth from resource depletion. Real-world examples are highlighted to illustrate the application of these sustainable principles, emphasizing their importance in achieving long-term environmental and economic resilience. Additionally, the chapter addresses the challenges of implementing these practices in rapidly growing urban areas and the necessity of adapting urban planning to accommodate future growth. It underscores the importance of collaboration between governments, industries, and communities to foster sustainable urban living. The discussion concludes with strategies for advancing sustainable cities, particularly in the context of developing countries where urbanization pressures are most intense.