This paper investigates the relationship between fiscal decentralisation and economy-wide disposable income inequality. Drawing on a dataset of up to 20 OECD countries over a period from 1996 to 2011, a regression analysis is performed, relating several indicators of national income inequality and a wide array of fiscal decentralisation indicators. The results indicate a weak, inequality-reducing relationship between decentralisation and 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. It shows that 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 increase the gap between lower and middle incomes. Interpreting these effects jointly, it seems that mainly middle income earners benefit from fiscal decentralisation. Finally, some insights on decentralisation and regional income inequality are presented. At first sight, fiscal decentralisation does not seem to be associated with income sorting in large jurisdictions, but a more fine-grained analysis is required to answer this question.