In recent decades, federal and unitary countries have increasingly adopted or deepened regional governance reforms, especially in the OECD and Europe, but also in Asia, America and to a lesser extent Africa. Approximately two-thirds of countries around the world have increased the power of regions over the last 50 years. This trend has happened in parallel with countries increasingly embedding a territorial approach into policy-making at the national and subnational levels. This process, however, does not follow a linear path. The rationale behind regional governance reforms differs from country to country, and over time, leading to a broad spectrum of governance models with varying institutional and financing arrangements. Taking stock of these trends, this report provides key data on regional governance reforms and their drivers, with a focus on the role of regions in the COVID-19 crisis response. The report also presents an innovative typology of regional governance models across OECD countries and the multi-level governance instruments that enable sound regional governance and help ensure these arrangements effectively serve their purpose.