ABSTRACT Each year, hundreds of thousands of people immigrate to the United States seeking a better way of life, and still hundreds of thousands more become citizens. Some spend time living in public and subsidized housing, sponsored by the Department of Housing and Urban Development (HUD), and, each year, thousands of these individuals attain citizenship. This paper presents an econometric analysis of the propensity of noncitizens living in HUD-sponsored housing to naturalize. Providing housing and other forms of public assistance to noncitizens is controversial but the fact of the matter is that, under current rules, many qualify for aid so, facing that fact, an important contribution of this research is to identify the type of program that works best in the context of broader national objectives. The key finding is that the market-based approach of the housing choice voucher program—and the spatial mobility it facilitates—significantly and substantively contribute to naturalization.