ObjectivesThe aim of the paper is to measure innovation capital of Polish cities and verify whether its dispersion changed.Material and methodsData was retrieved from the Local Data Bank provided by Statistics Poland. The sample consists of 18 Polish cities. The research period covers years 2014-2021. The TOPSIS method was applied to build the innovation capital index of cities and sigma convergence of innovation capital was verified.ResultsThe findings indicate relatively high cross-sectional disparities in the vast majority of the investigated indicators of cities’ innovation capital. The largest disparities were identified for the number of higher education graduates and the new registered enterprises in high-tech services sector. The constructed composite indicator - innovation capital index took the highest average values in the analysed period for Wrocław, Poznań, Kraków, Warszawa, and Lublin, whereas Gorzów Wielkopolski, Zielona Góra, Bydgoszcz, and Białystok achieved the lowest values. The sigma convergence analysis revealed that the differentiation of innovation capital in Polish cities remained at a similar level and there was no convergence in this area.ConclusionsInnovation capital plays a key role in the development of urban economy. Given the complexity of innovation capital, its measurement should comprise a set of indicators reflecting both output and input dimensions. Identification of spatial patterns of innovation capital distribution should enable to adjust smart specialization strategy to territorial characteristics of a given city.