This article uses life course theory and family bargaining theory to explore how decisions over schooling are negotiated in poorer Mexican families for whom compulsory basic education is a luxury. It explores educational decision making by conceptualizing education in terms of the way it meshes with other social relations and institutions across the life span. This article is based on a case study of a public "secundaria" (lower secondary school) located in a marginal area on the outskirts of Guadalajara, in the state of Jalisco, Mexico. Although the data were collected from one school, the theoretical framework proposed is intended to be informative for schools and populations sharing similar conditions, namely, economic insecurity that makes it hard for parents to plan ahead to support their children's schooling or to invest in their own futures, lack of integrated social security mechanisms that facilitate school attendance and support households across the life span, and a system that delegates responsibility for guaranteeing educational rights to families but in which failure to attend school is not formally sanctioned. (Contains 16 footnotes.)