Despite widespread agreement among international organizations on the importance of healthy early childhood development, monitoring of national action on the provision of pre-primary education has been limited. This paper presents a quantitative approach to monitoring the world’s progress on the United Nations (UN) sustainable development goal (SDG) target 4.2 to “ensure that all girls and boys have access to quality early childhood development, care and pre-primary education.” A rigorous approach was used to create a new quantitative globally comparable database of indicators for policies that mandate the provision of national pre-primary education for 86% of UN member states. This dataset was analyzed to examine global inequalities in the provision of universal pre-primary education and revealed that 43% of countries, and only 3% of low-income countries, provide tuition-free pre-primary education. Just under 25% of countries offer tuition-free pre-primary education for two or more years. This contrasts sharply with primary education, which is provided tuition-free in 96% of countries. To illustrate how this data can contribute to the examination of the relationship between policy and outcome, it is used in a regression analysis. Additional global data collection on the quality of pre-primary education would further enhance efforts to monitor policies that play key roles in the fulfillment of target 4.2, and support the achievement of the United Nations sustainable development goal on education.