The timeless question of what holds the world, a society together, is particularly urgent in the face of current challenges such as polarization, civil wars, and state collapse. While the factor "religion" is increasingly perceived in the social sciences, there is still a need for research on the empirical analysis of different aspects of religion with regard to the cohesion of countries in a global comparative perspective. Thus, I examine the role of religion for the social cohesion of states worldwide in a multi-level empirical analysis. For that, "social cohesion" is understood as a multidimensional construct that manifests itself in socio-political relations between citizen-citizen (horizontal level) and citizen-state (vertical level). Core dimensions are social/institutional trust, inclusive social/national identification, social/institutional responsibility and social/political engagement. "Religion" is conceptualized at the individual level with the dimensions believing (intensity/content of faith), behaving (private/social religious practice) and belonging (religious affiliation). At the macro level, religious vitality, religious diversity and state-religion relations are examined. For empirically measuring these dimensions, I use data from international surveys (e.g. World Values Survey, International Social Survey Programme) and databases (e.g. World Bank, Pew Research Center, State and Religion Project by J. Fox). The results of my thesis shall make both a scientific and socio-political contribution to a highly topical field.