This dissertation contains three essays on Urban Economics. The first two chapters study the impact of land-use regulation on economic development. Many countries have land-use regulations to preserve farmland from urban land expansion. In Chapter 1 and 2, I show that such regulations can distort economic activity across sectors and locations at a substantial cost to aggregate welfare in developing countries during urbanization. Specifically, I study a major policy restricting farm-to-urban land conversion in China - the Farmland Red Line Policy - to provide causal evidence on the impact of land-use regulation on local development measured by GDP and population growth. The policy imposes a barrier to urban land development, the strength of which depends on exogenous local geographical features. In Chapter 1, I show that a greater barrier significantly reduces urban land supply, lowers GDP, and decreases population. Findings in Chapter 1 raises the question about the aggregate impact of the Farmland Red Line Policy. Therefore, in the second chapter, I develop a quantitative spatial equilibrium model that features endogenous land-use decisions in order to understand the aggregate impact of the policy. According to the model, the policy causes an excess supply of farmland and an under-supply of urban land, and the extent of such land misallocation varies across locations due to their local geographical features. In the constrained equilibrium, the spatial and sectoral mobility of workers implies that land misallocation leads to labor misallocation. The calibrated model reveals that the welfare of workers would have been 6% higher in 2010 if the policy had not been implemented. Moreover, a cap-and-trade system that achieved the same aggregate level of farmland would have been far less costly in terms of welfare. The results suggest that fast-growing economies in developing countries need to design land-use policies carefully, as the welfare costs of poorly designed policies can be substantial. In Chapter 3, I test the impact of team size on one's publication output among US university economists from 1996 to 2011. I construct a database of affiliation and publication history for all US university economists using the publication information from the Scopus Database. University funding revenue from government appropriation and private gifts is used as an instrument for the total number of economists at a university. I find that a 10% increase in team size raises one's publication on top 5 economic journals by 30%. Moreover, the team size effect disappears once crossing the affiliation border: having more economists in a nearby affiliation does not affect one's output. Finally, increasing chances to coauthor with colleagues when being part of a larger team helps explain the team size effect.