The attraction of smart cities lies in the idea that increasing information and communication technology (ICT) and data-informed activities will lead to more efficient, better connected, and more creative cities. However, the ongoing technological transformation is largely driven by the desire to develop ICT-led markets. Common themes across the early leaders in the field are the creation of positive business environments with institutional collaboration and citizen-centric service delivery. Although smart cities have the potential to make a significant contribution to the urban sustainability agenda, this has not yet been realised. The New Urban Agenda (UN 2017) explicitly mentions the role of smart cities in facilitating a paradigm shift in city management, yet pathways to achieve urban sustainability remain unclear. This brief presents an alternative understanding of smart cities, big data and the internet of things (IoT), and identifies specific policy actions to address urban sustainability in the context of the Sustainable Development Goals (SDGs), focusing on goals 11 and 13