Examining the research literature in housing, planning, and the social sciences, this paper argues that the housing crisis of the 1980s spawned a new environmental stress, housing affordability, which has had devastating consequences for economically vulnerable single mothers and their children. A conceptual framework is developed that depicts how the housing affordability dilemma generates a pathway to homelessness beset by four pinchpoints: a resource squeeze that precipitates loss of permanent housing; residential mobility that destabilizes families; discrimination in the housing market that constrains housing choices; and multiple stressors that demoralize a fragile family system. Implications of these findings are discussed, including attention to housing problems of single mothers in both social policy and direct practice arenas.