While global enrollment in primary education has increased significantly particularly since it became a target of the United Nations "Education for All" initiative and one of the Millennium Development Goals, primary completion rates have remained virtually unchanged since 1999. Evidence from studies of individual programs in a range of countries suggests that enrollment in pre-primary education can improve school readiness and achievement in primary school, and therefore, potentially raise primary completion rates. As research has also found that provision of free education is associated with higher enrollment, we hypothesize that provision of free and compulsory pre-primary education will be associated with higher primary school completion rates. Further, we hypothesize that free pre-primary education will have the largest impact where completion rates have been lowest. Using a database of quantitative, globally comparable measures of national provision of free pre-primary education we created, and data from UNESCO's Institute for Education Statistics, we analyze the 104 nations with complete data. We conduct multivariate quantile regression analyses. We find that, controlling for national income and level of urbanization, provision of at least 1 year of free and compulsory pre-primary education is associated with a nearly 10 percentage point increase in primary school graduation rates for countries at the median and a 12 percentage point increase in rates for primarily low- and lower-middle-income countries at the lower end of the distribution.