Immigration poses individual or collective economic risks that might increase citizen support for government redistribution, but it can also generate fiscal pressure or undermine social solidarity to diminish such support. These offsetting conditions obscure the net effects of immigration for welfare states. This article explores whether immigration's effects are mediated by the economic and social integration of immigrants. Integration can be conceptualized and measured as involving the degree to which immigrants suffer unemployment rates, depend on welfare-state benefits, and harbor social attitudes similarly to the native population. Such integration may alter how immigration reduces solidarity and imposes fiscal and macroeconomic pressures, but does not much alter how immigration spurs economic risks for natives. Where migrants are more integrated by such measures, immigration should have less negative or more positive implications for native support for government redistribution and welfare states than where migrants are less integrated. The article explores these arguments using survey data for twenty-two European countries between 2002 and 2010. The principal finding is that economic integration, more than sociocultural integration, softens the tendency of immigration to undermine support for redistributive policies.