This paper studies the macroeconomic effects of publicly funded ('free') secondary schooling in the developing world. Our analysis is based on an overlapping generations model of human capital accumulation that we estimate to match experimental evidence on the effects of scholarships for poor but talented students in Ghana. The model predicts that nationwide free secondary schooling increases average education levels but leads to only a modest gain in GDP per capita. The human capital gains from expanded education access are offset by lost income during schooling years and dampened by negative selection of new students entering secondary school. An alternative policy that spends the same resources improving school quality has significantly larger effects.