I study the effect of taste-based discrimination on the assimilation decisions of immigrant minorities. Do discriminated minority groups increase their assimilation efforts in order to avoid discrimination and public harassment or do they become alienated and retreat in their own communities? I exploit an exogenous shock to native attitudes, anti-Germanism in the United States during World War I, to empirically identify the reactions of German immigrants to increased native hostility. I use two measures of assimilation efforts: naming patterns and petitions for naturalization. In the face of increased discrimination, Germans increase their assimilation investments by Americanizing their own and their children’s names and filing more petitions for US citizenship. These responses are stronger in states that registered higher levels of anti-German hostility, as measured by voting patterns and incidents of violence against Germans.