We explore how state and local policies in labor, health, education, language, community and neighborhood environments, deportation, and state-authorized identification can reduce or exacerbate HIV vulnerability among Latino migrants in the United States. We reviewed literature on Latino migrants and HIV risk, on the structural-environmental contexts experienced by Latino migrants, and on the many domains in which policies influence those contexts. To illustrate the pathways through which policies across multiple sectors are relevant to HIV vulnerability, we describe how policies shape 2 mediating domains (a climate of hostility toward Latino migrants and the relative ease or difficulty of access to beneficial institutions) and how those domains influence behavioral risk practices, which increase vulnerability to HIV. This argument demonstrates the utility of considering the policy context as a modifiable element of the meso-level through which structural factors shape vulnerability to HIV. This approach has specific relevance to the consideration of HIV prevention for Latino migrants, and more generally, to structural approaches to HIV prevention.