AbstractThe Effects of Housing Vouchers on Welfare Families was an experimental evaluation that examined the effects of housing assistance on low‐income families eligible for or receiving Temporary Assistance for Needy Families. Household‐based rental vouchers were provided to participants under the Welfare to Work Voucher program sponsored by the U.S. Department of Housing and Urban Development from 2000 through 2004. Vouchers were randomly assigned to eligible program participants in six sites across the country, sample members were tracked over about five years, and the effects of vouchers on homelessness and crowding, household composition, housing mobility, neighborhood quality, employment and earnings, and other aspects of family well‐being were measured. Vouchers significantly reduced homelessness, crowding, household size, and the incidence of living with relatives or friends, but had no effect on marriage or cohabitation. Vouchers increased housing mobility, while reducing the number of subsequent moves, and resulted in small improvements in neighborhood quality.