Cities worldwide are challenged by a high complexity of acute and chronic problems, including challenges related to economic development, social polarisation and segregation as well as climate change and ecological degradation. While all of these problems are complex in themselves, they are also interrelated. Addressing them in a meaningful way requires governance systems with systemic capacities to deal with complexity. In order to create resilience in urban systems, cities need to be able to learn, adapt and transform across sectors and levels. One definition of urban resilience is the capacity of individuals, communities, institutions, businesses, and systems within a city to survive, adapt, and grow regardless of the kinds of chronic stress and acute shocks they experience. This is the definition the Rockefeller Foundation adopts in its mission to promote the well-being of humanity throughout the world by facilitating the building of resilience in cities worldwide through its 100 Resilient Cities Programme, launched in 2013. Rotterdam is one of the first cities to participate in this programme. The city has been a front-runner in preparing for climate change and striving for urban sustainability. This paper assesses the concept of urban resilience, introduces the Rockefeller Foundation's effort in building city resilience worldwide and illustrates this with the Rotterdam case. •The City Resilience Framework raises questions concerning what exactly constitutes resilience and a resilient city.•The City Resilience Framework intends to inspire cities to reflect upon the extent to which critical functions are capable of adapting to new situations induced by shock or stress.•100RC offers an approach, but also a platform for debate between academics and stakeholders in cities worldwide.