This paper deals with the effects of political decentralisation on economic growth in Spain, an issue that has generated heated debates in recent decades. Our analysis of the last three and a half decades, a period characterised by the weak narrowing of the income per capita gap within regions, does not offer conclusive results on convergence and points to the importance of alternative factors. Several proxies were used to capture the decentralisation process. We also studied some potential interactions between decentralisation and other variables. All in all, our empirical evidence shows robustly that transferring more responsibilities to subnational governments does not significantly affect growth in any sense.