The potential of open data as a resource for driving citizen-led urban innovation relies not only on a suitable technical infrastructure but also on the skills and knowledge of the citizens themselves. This paper describes how a smart city project in Milton Keynes, UK, is supporting multiple stages of citizen innovation, from ideation through to citizen-led smart city projects. This approach encounters challenges when engaging with citizens in identifying and implementing data-driven solutions to urban problems. The majority of citizens have little practical experience with the types of data sets that might be availa- ble, nor possess the appropriate skills for their analysis and utilisation for ad- dressing urban issues, or finding novel ways to hack their city. We go on to de- scribe the Urban Data School, which aims to offer a long-term solution to this problem by providing teaching resources around urban data sets aimed at rais- ing the standard of data literacy amongst future generations. Lesson resources that form part of the Urban Data School have been piloted in a primary and two secondary schools in Milton Keynes.