This paper examines the link between average city size and aggregate economic growth in a total of 114 countries for the period between 1960 and 2010. The analysis – which includes pooled two-stage least-squares (2SLS), panel data analysis, system generalized method-of-moments (GMM) estimator, and an instrumental variable (IV) approach – finds that, in contrast to the prevailing view, there is no universal positive relationship between average city size and economic growth and that the results vary between high-income and developing countries. In high-income countries, there is consistent evidence of a positive albeit decreasing link between city size and economic growth. In contrast, the relationship does not hold for developing countries,...