A UNESCO World Heritage Site is a specific site (such as a forest, mountain, lake, desert, monument, building, complex, or city) that has been nominated and confirmed for inclusion on the list maintained by the international World Heritage Programme administered by the UNESCO World Heritage Committee, composed of 21 State Parties (countries) which are elected by the General Assembly of States Parties for a fixed term. The programme aims to catalogue, name, and conserve sites of outstanding cultural or natural importance to the common heritage of humanity. Under certain conditions, listed sites can obtain funds from the World Heritage Fund. The programme was founded with the Convention Concerning the Protection of World Cultural and Natural Heritage, which was adopted by the General Conference of UNESCO on 16 November 1972. Since then, 184 (as of July 2007) States Parties have ratified the convention.

As of 2007, a total of 851 sites are listed: 660 cultural, 166 natural, and 25 mixed properties, in 142 States Parties. UNESCO references each World Heritage Site with a unique identification number; but new inscriptions often include previous sites now listed as part of larger descriptions. As a result, the numbering system currently ends above 1200, even though there are fewer on the actual list.

Each World Heritage Site is the property of the country on whose territory the site is located, but it is considered in the interest of the international community to preserve each site for future generations of humanity. The protection and conservation of these sites are a concern of all the World Heritage countries.