The past decades have seen an undeniable trend towards decentralisation and greater diversity of multilevel governance arrangements around the world. Decentralisation outcomes depend on the way decentralisation is designed and implemented. A key issue for the effectiveness of decentralisation is linked to the way responsibilities are assigned across levels of government. The literature on fiscal federalism has provided some general guidelines that provide a point of departure for thinking about the assignment of responsibilities. However, when looking at country practices, the difference between theory and country experience appears to be significant. This paper reviews the trends, challenges and good practices in the way responsibilities are distributed across levels of government. It concludes with a set of guidelines for policy-makers, to better assign responsibilities across levels of government for more effective decentralisation.