Persistent barriers to universal access to medicines are limited social protection in the event of illness, inadequate financing for essential medicines, frequent stock-outs in the public sector, and high prices in the private sector. We argue that greater coherence between human rights law, national medicines policies, and universal health coverage schemes can address these barriers. We present a cross-national content analysis of national medicines policies from 71 countries published between 1990-2016. The World Health Organization's (WHO) 2001 guidelines for developing and implementing a national medicines policy and all 71 national medicines policies were assessed on 12 principles, linking a health systems approach to essential medicines with international human rights law for medicines affordability and financing for vulnerable groups. National medicines policies most frequently contain measures for medicines selection and efficient spending/cost-effectiveness. Four principles (legal right to health; government financing; efficient spending; and financial protection of vulnerable populations) are significantly stronger in national medicines policies published after 2004 than before. Six principles have remained weak or absent: pooling user contributions, international cooperation, and four principles for good governance. Overall, South Africa (1996), Indonesia and South Sudan (2006), Philippines (2011-2016), Malaysia (2012), Somalia (2013), Afghanistan (2014), and Uganda (2015) include the most relevant texts and can be used as models for other settings. We conclude that WHO's 2001 guidelines have guided the content and language of many subsequent national medicines policies. WHO and national policy makers can use these principles and the practical examples identified in our study to further align national medicines policies with human rights law and with Target 3.8 for universal access to essential medicines in the Sustainable Development Goals.