Social security beneficiaries and the general public alike are concerned about the financial solvency of the social security program. But how much do they know about how the system works? This study analyzes the determinants of knowledge about social security among nonremarried widows having children under their care. It builds a research model based on the economic theory of rational decision making. Using ordinary least squares regression estimation techniques, the level of knowledge about specific social security provisions is regressed on family income, implicit tax rate, number of children, human capital variables, and other demographic and locational variables. The findings support the economic theory applied to this study. Widows who gain more by knowing social security provisions indeed know more about them than those who gain less