While the politics of globalization and welfare state retrenchment have garnered much attention in recent years, scholarly research on public support for welfare state expenditure is comparatively sparse. Furthermore, new pressures, specifically international immigration and resulting ethnic heterogeneity, add a new challenge to the welfare state. In this article, I analyse support for social welfare expenditure in Sweden—the country that spends the greatest percentage of its GDP on social expenditure and, until recently, remained relatively ethnically homogeneous. Results from multilevel models reveal that multiple measures of immigration at the county-level have significant negative effects on support for the welfare state. Moreover, recent immigration has a negative effect on attitudes towards universal spending. Thus, this analysis provides clear evidence that ethnic heterogeneity negatively affects support for social welfare expenditure—even in Sweden.