Abstract_ This paper explains differential rates of lifetime homelessness in the United States and Europe, as indexed by household surveys, from income inequality and tax and benefit programmes that increase or reduce poverty. These lifetime rates do not reflect recent efforts to reduce homelessness in some countries. The United States and the United Kingdom have higher lifetime rates of homelessness, more income inequality and, especially in the US, less generous social welfare policies than most European countries. The meagreness of family benefits in the US seems particularly associated with family homelessness. Two groups of people experience high rates of homelessness everywhere : racial minorities and people who experience mental illness. This paper explains their higher rates of homelessness across nations in terms of four forms of social exclusion based on income, wealth, housing and incarceration, and offers experimental as well as correlational evidence that discrimination remains important, at least in the US, today. Relative levels of homelessness across societies stem from societal choices in these domains.