EU accession offers a unique opportunity to accelerate growth and raise living standards in the Western Balkans and Moldova. The paper suggests that GDP per capita could rise by about one-third within a decade under the right conditions. Realizing this potential will require three mutually reinforcing forces: domestic structural reforms anchored in the EU Acquis, deeper integration into the single market, and effective use of EU funding, contributing broadly similarly to the overall gain. The pathway for prosperity is productivity growth, which accounts for two thirds of income gains, driven by stronger institutions, better governance, and a more dynamic private sector. And enlargement is not a zero-sum game: existing EU members stand to benefit as well, especially if Europe continues to deepen its single market and unlock the full benefits of goods and services trade, capital, labor, and energy market integration.