The proliferation of government policies to manage immigration has led to the emergence of an interdisciplinary literature that evaluates policy effects on immigrant integration. This review synthesizes findings from evaluations of policies regulating legal status and citizenship, the labor market, welfare, settlement, education, and cultural rights. It concludes that policies lowering immigrants’ costs of adjustment to the host country are consistently more effective in promoting integration than policies incentivizing immigrant effort through withholding resources and regulating access to rights. Policy changes the behavior of both immigrants and native-born citizens through material and psychological pathways, and considering the decision making of each side and their interdependence is crucial for understanding why estimated effects of the same policy differ across contexts and for anticipating unintended consequences. For external validity and useful counterfactuals, a closer connection is needed between empirical research and theoretical models that explicitly account for the equilibrium nature of integration.