Fiscal constitutions comprise the set of rules and frameworks guiding fiscal policy that are enshrined in a country’s fundamental laws. This paper compares the fiscal constitutions of 15 federal countries by empirically assessing five building blocks: 1) the power of sub-national governments to conduct their own fiscal policy; 2) the degree to which sub-national governments are held responsible for fiscal policy outcomes; 3) the extent to which sub-national governments can shape fiscal policy of the federal level; 4) the strength of intergovernmental budget rules; and 5) the stability of fiscal policy arrangements. The results can be summarised as follows: Countries can be ranked along a single indicator, namely the degree of constitutionally guaranteed decentralisation. They can also be ranked along an indicator of institutional coherence which measures the extent to which building blocks “fit together”. From 1917 to 2013, fiscal autonomy and responsibility declined – except in the 80s and 90s of the 20th century – while co-determination and budget frameworks were strengthened, and institutional coherence rose. Simple correlations suggest that the extent of decentralisation hardly affects fiscal outcomes such as deficits, debt or vulnerability to crises, while institutional coherence (or incoherence for that purpose) does.