Fuzzy logic is adaptive and adjustable decision-making, hence having tremendous potential for mitigating the uncertainties underlying urban systems. The chapter discusses the application of fuzzy logic towards sustainable urbanization in the context of smart cities that must learn to accommodate dynamic and even less predictable parameters in energy, traffic, and environmental systems. With the increasingly urbanized population and the continuously growing need for effective infrastructure, the integration of fuzzy logic in a decision system can enhance the responses of a city towards change and uncertainties. This is attributed to the ability of sophisticated model approaches in bringing enhanced control over resources, optimized traffic movements, and maximization of energy sources while better management of the environment. The theory of fuzzy logic, urban systems case study of applications, their limitations, opportunities for adopting and incorporating within intelligent city development as a sustainable agenda is established.