Fiscal decentralisation might be partially responsible for rising income inequality by exacerbating competition between sub-national governments and compromising national government’s ability to redistribute. This paper investigates the relationship between fiscal decentralisation and economy-wide disposable income inequality. Drawing on a dataset of up to 20 OECD countries and covering the period 1996 to 2011, the analysis links a set of income inequality indicators and a wide array of fiscal decentralisation indicators. Results indicate that decentralisation might actually reduce income inequality, as measured by the Gini coefficient, but the effect is rather small and unstable across specifications. Fine-graining the analysis by using income percentile ratios, in turn, produces more significant and stable results. As such, the effects of fiscal decentralisation are not the same along the income distribution. While decentralisation tends to be associated with a reduction in income inequality between high incomes and the median, it is linked to a divergence of low income groups from the median, notably via sub-central tax autonomy. Transfers between levels of government also tend to be associated with an increase in the gap between lower and middle incomes. Interpreting these effects jointly, it seems that mainly middle income earners benefit from fiscal decentralisation.