This thesis investigates economic aspects of the measurement of fiscal decentralisation to establish how a nation's fiscal arrangements can be consistently measured, so they can be compared internationally. A new index of fiscal decentralisation is developed that reflects two key elements of the theory of fiscal decentralisation: the fiscal autonomy of subnational governments; and their fiscal importance. The role of fiscal inequality in subnational governments' public finances is also considered. The thesis consists of nine chapters which are distinct but closely related. These nine chapters can be divided into the three