The World Database on Protected Areas (WDPA) is the largest assembly of data on the world's terrestrial and marine protected areas, containing more than 260,000 protected areas as of August 2020, with records covering 245 countries and territories throughout the world. The WDPA is a joint venture between the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) and the International Union for Conservation of Nature (IUCN) World Commission on Protected Areas (WCPA).

Data for the WDPA is collected from international convention secretariats, governments and collaborating NGOs, but the role of custodian is allocated to the Protected Areas Programme of UNEP-WCMC, based in Cambridge, UK, who have hosted the database since its creation in 1981. The WDPA delivers invaluable information to decision-makers around the world, particularly in terms of measuring the extent and effectiveness of protected areas as an indicator for meeting global biodiversity targets. In October 2010, UNEP-WCMC launched the social media-based website Protected Planet, which allows users to interact with and improve the data that is currently recorded on the World Database on Protected Areas.

Every two years, the Protected Planet Report is published by the UNEP-WCMC. This report provides a comprehensive evaluation of the status of the world's protected areas and offers strategic recommendations to meet international conservation goals.

The WDPA uses the IUCN's definition of a protected area as the main criteria for entries to be included in the database. The database contains comprehensive information on the different types of protected areas ranging from those strictly protected for conservation purposes to those where sustainable use of natural resources is allowed; and includes government, co-managed, private and community-managed areas. The IUCN's World Commission on Protected Areas gives international guidance on the categorisation of protected areas, through its Protected Area Management Categories. These categories are recognised worldwide and facilitate a global system for defining and recording protected areas. Within the WPDA the IUCN Management Category of a protected area is listed (if one has been assigned/reported) as part of the information on a protected area.

Data held in the WDPA is made up of both 'attribute' and 'spatial' information. Attribute data refers to the characteristics of a protected area, such as its name, reported area and designation type. Spatial data is provided in the form of Geographical Information System (GIS) electronic maps, often referred to as shapefiles. These files provide information on the location (latitude & longitude) and spatial extent of a protected area, either as a midpoint location or a polygon that shows the boundaries of a protected area, which gives the indication of its size and shape. This is the form that the data takes on Protected Planet through which the data on WDPA is available for public use worldwide. The WDPA Development Team at UNEP-WCMC has a formal agreement with the Global Biodiversity Information Facility (GBIF) to integrate their network species occurrence data with the shapefiles of protected areas on the WDPA, which assists governmental, non-governmental and private organisations to visualise the density of species within a protected area.

Protected areas within the WDPA are assigned as having a national or international designation. Many protected areas fall into the category of being nationally designated, where they are designated within a country's national territory (including their maritime Economic Exclusive Zone) using the appropriate legislation or agreements. Internationally designated sites are primarily those of significant environmental, cultural or natural value that should be protected irrespective of the territory on which they are located. These areas are often recognized, preserved and protected under an international treaty or convention. In some cases, an internationally recognized site may be nationally designated as well.

The most common international conventions under which protected areas are designated are:

UNESCO seeks to encourage the identification, protection and preservation of cultural and natural heritage around the world considered to be of outstanding value to humanity. This is embodied in an international treaty called the Convention concerning the Protection of the World Cultural and Natural Heritage, adopted by UNESCO in 1972.