In urban infrastructure the investment decisions taken today will shape tomorrow. Despite the critical importance of infrastructure for urban development, financing to scale up smarter, more sustainable urban infrastructure remains an immense challenge, particularly in emerging and developing economies. This paper provides an overview of financing challenges and opportunities for urban infrastructure to support "The Sustainable Infrastructure Imperative: Financing for Better Growth and Development", the 2016 flagship report of the Global Commission on the Economy and Climate. It sets out the landscape of urban infrastructure financing, identifies key barriers to delivering smarter, more sustainable urban infrastructure in cities, suggests policy levers and instruments that have been deployed successfully in various countries and cities, and concludes with some recommendations for decision-makers.