Abstract
The chapter dwells on the concept of fiscal federalism taking a comparative constitutional law standpoint. After an initial reconstruction of the theories underlying its origin and evolution over time and space, the interdisciplinary dimension of the studies on fiscal federalism is explored in search of a (non-)definition. The chapter then moves on to a comparative constitutional analysis through the investigation of the concept of financial constitution and later through a comparative legal analysis of the foundations of fiscal federalism. A case study approach is adopted and the current de jure and de facto allocation of financial and fiscal powers, as well as the intergovernmental (fiscal) institutions are examined, to figure out the functioning of financial relations among different levels of government.