Metropolitan regions are generally seen as drivers for territorial development in the national context, as well as drivers for economic, social and cultural development on a European and global scale. Many border regions dispose of specific potentials but also specific barriers for a cross-border polycentric metropolitan region. However, cross-border areas appear to be systematically underestimated in their development opportunities so that awareness about specific advantages needs to be improved. This is why this project addresses cross-border metropolitan regions in Europe in relation to the policy aim of polycentric development. It aims at identifying criteria, potentials and governance practices based on available ESPON evidence for polycentric cross-border metropolitan regions in Europe and proposing options for development strategies towards a multilevel approach for two case study regions (Upper Rhine Region and the Greater Region).