Over the last two decades, regional inequalities have remained significant, and have grown within many OECD countries. Impacts of recent shocks, including the COVID-19 pandemic and Russia’s war of aggression against Ukraine, and megatrends, threaten to widen these gaps between regions, deepening the longstanding geography of inequalities. This report, Regional Outlook 2023 – The Longstanding Geography of Inequalities, provides novel evidence on the evolution of inequalities between OECD regions across several dimensions (including income and access to services) over the past twenty years. It sheds light on the role of productivity to address regional inequalities. It also looks at the costs of regional inequalities, which can weaken the economic, social, and political fabric, and lead to a geography of discontent. Furthermore, the report explores forward-looking scenarios for regions as part of ongoing reflections to future-proof regional development policy and secure social cohesion. Finally, it provides a policy roadmap to guide governments’ efforts to reduce persistent regional inequalities now and in the future.