The housing choice voucher program was designed with two main goals in mind: to eliminate concentrations of poverty and the social problems it causes and to provide poor households with greater access to higher-opportunity neighborhoods. However, research suggests that voucher holders would like to move to higher-opportunity neighborhoods, but often are unable to do so. One of the most prominent reasons for this is that, in most cities and states, local law allows landlords to discriminate against potential tenants on the grounds of their "source of income" (SOI). This article reviews the literature on discrimination of voucher recipients and the potential for SOI antidiscrimination laws to mitigate some of these negative outcomes.