In today’s urbanizing world, cities have not only physical infrastructures, such as road networks, utilities, or buildings, but also comprise a knowledge infrastructure ranging from lowlevel sensor networks to public databases and social media streams. The data emerging from all those sources is a very precious resource to make cities more intelligent, innovative and integrated beyond the boundaries of isolated applications. Although such “big data” has been popularised in the media as the “new currency", fuelling a future vision of contextual systems that will transform our cities, the reality is that we just began to recognise significant research challenges across a spectrum of topics (that must be addressed to realise the vision: information retrieval, knowledge representation, semantic reasoning, data mining and many others). In fact, if we cannot find the ways to harvest the city data and to transform it into tangible insights, our vision of offering innovative solutions to the realworld problems of the cities will not go beyond an expressed wish. This workshop addresses such a timely issue to turn the city data into insightful information. It covers a broad range of topics rooting from different scientific fields, in order to enable novel research to mine important patterns from city data and to apply them in various emerging application areas, such as smart mobility/transportation, smart tourism or smart participation. Those application areas pose unique challenges giving the opportunity to researchers in different communities, including database, knowledge management and information retrieval, to discuss the emerging research topic of pattern mining in smart cities, identifying its unique challenges, opportunities and future directions.