The problem of low naturalization rates in the United States has entered policymakers’ agendas in light of the societal gains associated with citizenship and an increasing number of foreign-born residents. Nevertheless, there is little evidence on what policy interventions work best to increase naturalization rates. In this research, we show that the standardization of the fee waiver for citizenship applications in 2010 raised naturalization rates among low-income immigrants. These gains were particularly sizable among those immigrants who typically face higher hurdles to accessing citizenship. These findings have implications for policymakers interested in designing policies that help disadvantaged immigrant groups overcome barriers to citizenship.