By the end of the century, more than 85 per cent of the global population is projected to reside in cities. The process of urbanisation and the transformation of cities are pivotal to the global changes witnessed in the twenty-first century. Cities drive economic growth and foster technological innovation, creating spillover effects through agglomeration economies and significantly influencing climate change. The 2030 Agenda for Sustainable Development and Sustainable Development Goals (SDGs) and the Paris Climate Agreement on meeting net-zero emissions underscore the urgent and immediate need for sustainable urban development and the central role of cities. This chapter aims to achieve three primary objectives: firstly, to offer a comprehensive review of urban transformation; secondly, to examine the imperative and notion of productive cities and urban sustainability; and, thirdly, to support with real experiences and cases of productive and sustainable cities and to draw essential lessons to enhance cities’ contributions and conclude with a synthesis. Drawing from development economics and urban development studies and leveraging the author’s policy experience as a former mayor, minister of urban development, and policy leader, the chapter is structured into four sections, complemented by an introduction and conclusion. Under Brazil’s chair, the 2024 Rio G20 Summit 2024 will contribute to elevating the urban transformation agenda.