The world’s protected area network is constantly changing, and the dynamics of this network are tracked using the World Database on Protected Areas (WDPA). This database evolved from a list of protected areas first mandated by the United Nations in 1959, and it now informs the key indicators that track progress toward area-based conservation targets. In this capacity, the WDPA illuminates the role of protected areas in advancing a range of international objectives and agreements, including the Convention on Biological Diversity and the Sustainable Development Goals. Despite ongoing challenges in maintaining such a complex global dataset, the WDPA is continuously improving and taking advantage of new technology, making it widely applicable to diverse users, including those in sectors far from its original intended audience. In the future, the WDPA will expand to include areas that contribute to conservation and sustainable use outside of formal protected areas, and will increasingly link to other key global datasets. These innovations in the way the WDPA is managed and used will deliver vital knowledge to support a sustainable future for biodiversity and people globally. The World Database on Protected Areas has evolved since 1959 to become an essential resource for monitoring global progress in terrestrial and marine habitat protection. This Review illustrates the users and uses of the WDPA, its history of quality improvements and challenges for future development.