Abdulaziz I. Almulhim
Cities increasingly face urban sustainability challenges due to rapid urbanization, climate pressures, and infrastructure demands. In response, smart city frameworks have emerged as transformative strategies that promote sustainability, efficiency, and resilience. Among the enabling technologies, the integration of the Internet of Things (IoT) and blockchain is gaining traction for supporting data-driven, transparent, and inclusive forms of sustainable smart cities. This systematic review analyzes peer-reviewed studies to examine how IoT and blockchain contribute to smart and sustainable urban development. The findings are organized into five thematic areas: (1) applications of IoT and blockchain for sustainable urban development; (2) operational applications across urban sustainability sectors such as energy, mobility, waste, and environmental management; (3) blockchain-enabled urban governance mechanisms including smart contracts, identity systems, and emergency response; (4) direct citizen engagement through transparent participation platforms and incentive-based systems; and (5) challenges and opportunities associated with IoT and blockchain technologies in the context of sustainable city development. In addition, the study proposes a conceptual framework that illustrates how IoT and blockchain integration support sustainable urban innovation. The review highlights the transformative potential of IoT–blockchain convergence in shaping future smart and sustainable cities and aligns with the United Nations Sustainable Development Goal 11.