Abstract: Why does schooling attainment vary widely across countries? Why are differences in schooling attainment highly persistent? I show that cross-country differences in schooling are related to political institutions, such as democracy and local democracy (political decentralization), which are affected by colonial factors. By using the number of native cultures before colonization as an instrument for political decentralization, I show that, after controlling for the causal effect of income on schooling, the degree of democratization positively affects the development of primary education, whereas political decentralization has a positive and significant impact on more advanced levels of schooling.