Smart cities rely on massive volumes of multidimensional data generated through IoT devices, sensors, citizen applications, public services, and private platforms. Integrating these diverse datasets into a unified ecosystem requires robust data integration models and governance frameworks that ensure interoperability, data quality, security, and ethical use. This research article reviews existing smart city architectures and proposes an integrated “Smart City Data Integration & Governance Model (SC-DIGM)” that incorporates layered data processing pipelines, federated interoperability standards, cross-agency governance, and ethical decision-making. The model aims to guide city administrators, policymakers, technology providers, and researchers in developing a holistic framework for data-driven urban innovation.