In the last decade, a number of smart city initiatives have flourished around the world. While the literature is ripe with descriptions of those projects and pioneering cities, there is far less systematic research on why some cities are more advanced than others. As single locating entities, cities are posited to have strong geographic rootedness. Hence, spatial and socio-economic context, considered as the main stimulant of organizational innovation, can be particularly important for cities. We investigate 22 Swiss cities with smart city projects and use fuzzy-set Qualitative Comparative Analysis to determine the configuration of conditions that make some cities more advanced than others in their smart city development. Results indicate that a configuration of high share of service sector, presence of research institutions and high urban density is sufficient for the outcome, whereas population size, new residential development and participation to international networks appear as less important. By providing insights into the spatial and socio-economic underpinnings of smart city development, the study contributes to the understanding of the geographies of smart cities.