Mobilizing the world’s financial centres is essential to make progress on climate change and sustainable development. The momentum towards a sustainable financial system is clear: integrating environmental, social and governance (ESG) factors into investment portfolios is delivering superior returns, the green bond market continues to expand, governments are developing national roadmaps and financial regulators are starting to incorporate environmental risks into market supervision. This momentum is, however, insufficient to deliver the Paris Agreement and the Sustainable Development Goals (SDGs). The world’s financial centres now have a historic opportunity to help close this gap by accelerating the expansion of green and sustainable finance. Financial centres are the locations where the demand for and supply of finance come together. They are the places where green and sustainable financial services will need to be scaled up across banking, capital markets, fintech, insurance and investment. This report presents the case for strategic action by financial centres and introduces the new International Network of Financial Centres for Sustainability that was launched in Casablanca in September 2017. Financial centres generate a powerful clustering effect that can also be deployed to drive sustainable finance.