This paper introduces urbanization as an important driver of government size. Using panel data of 175 countries from 1960–2010, urbanization is closely linked to a larger public sector, especially related to education, health care, and social issues. Various robustness checks confirm this finding. Analyzing state-level public spending in Colombia and Germany confirms our hypothesis on the subnational level. On the microeconomic level, people in urban areas acknowledge more responsibility of governments and are more in favor of redistribution. This finding can help explain the evolution of government size, but also predict present and future needs of urbanizing areas.