Using panel data for non-OECD countries covering the period 1970-2012, this paper analyzes the impact of the duration of primary education on school enrollment in secondary education. The empirical results show that in those countries where the duration of primary education is increased, the enrollment rate in secondary education decreases, and the opposite is observed in those countries where the duration of primary education is reduced. These results are in line with the fertility model approach; that is, in developing and underdeveloped countries parents do not have incentive to pursue further education for their children given the high perceived present economic value of children. JEL Classification: I21, I25, I28 Keywords: primary education, secondary education, school enrollment, education policy, developing countries, school duration