This chapter examines Waqf, Islamic endowment, as a powerful tool for enabling sustainable cities and communities. It looks at the history and legal basis for Waqf and its diversification and application in different Islamic societies. In this context, Waqf has many characteristics for community development across social, economic, and environmental dimensions. The chapter examines Waqf through the analysis of legal mechanisms regulating Waqf geared towards the local, and ordinary citizen experience, but also includes traditional arrangements and "new" Waqf arrangements (e.g. corporate Waqf, Waqf sukuk). The chapter includes challenges and opportunities in Waqf management today for consideration and understanding. Lack of transparency and accountability for Waqf management and local political reform, is crucial because reform in these areas may prepare the development of Waqf to better achieve the Sustainable Development Goals (SDGs) and ensure resilient cities, through the complexity and diversity of Waqf processes.