Multi-level regulatory governance is becoming a priority in many OECD countries. High quality regulation at a certain level of government can be compromised by poor regulatory policies and practices at other levels, impacting negatively on the performance of economies and on business and citizens’ activities. The most common problems that affect the relationship between the public and the private sectors are duplication, overlapping responsibility and low quality. These affect public service delivery, citizen’s perception, business services and activities, as well as investment and trade. More positively, following certain principles and good practices for high quality regulation in a coherent way as well as facilitating co-ordination among regulatory institutions at different levels of government can bring improvements to the regulatory system as a whole.