This study uses a panel of sixty-four countries to test empirically various hypotheses about the causes of decentralization at the government level and in different functional spending areas. The empirical results find a negative impact of urbanization on decentralization. In the general case, a higher income per capita favors decentralization, with this effect being stronger for high-income countries. However, the use of functional measurements of decentralization shows that income per capita has a negative effect on health decentralization. Urbanization has a negative impact on the fiscal decentralization of health and education, and it has a positive effect on the share of housing expenditures being made by subnational governments.