Defence date: 10 June 2014Examining Board: Professor Nicola Pavoni, Università Bocconi (Supervisor) Professor Jérôme Adda, European University Institute Professor Jan Eeckhout, University College London Professor Omiros Papaspiliopouloos, Universitat Pompeu Fabra.In my thesis, I study the effects of agents' heterogeneity on labor market outcomes, with particular focus on sorting, performance, wages, and inequality. Chapter one studies multidimensional matching between workers and jobs. Workers differ in manual and cognitive skills and sort into jobs that demand different combinations of these two skills. To study this multidimensional sorting, I develop a theoretical framework that generalizes the unidimensional notion of assortative mat...