The United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Sites are places of importance to cultural or natural heritage as described in the UNESCO World Heritage Convention, established in 1972. Cultural heritage consists of monuments (such as architectural works, monumental sculptures, or inscriptions), groups of buildings, and sites (including archaeological sites). Natural features (consisting of physical and biological formations), geological and physiographical formations (including habitats of threatened species of animals and plants), and natural sites which are important from the point of view of science, conservation or natural beauty are defined as natural heritage. The United Kingdom ratified the convention on 29 May 1984, making its sites eligible for inclusion on the list.
There are 35 World Heritage Sites in the United Kingdom and the British Overseas Territories. Out of these sites, one site is located in both England and Scotland (the Frontiers of the Roman Empire), eighteen are exclusively in England, seven in Scotland, four in Wales, two in Northern Ireland, and one in each of the overseas territories of Bermuda, Gibraltar, the Pitcairn Islands, and Saint Helena. The first sites in the UK to be inscribed on the World Heritage List were Giant's Causeway and Causeway Coast; Durham Castle and Cathedral; Ironbridge Gorge; Studley Royal Park including the Ruins of Fountains Abbey; Stonehenge, Avebury and Associated Sites; and the Castles and Town Walls of King Edward in Gwynedd in 1986. The most recent site listed was Gracehill, as a part of transnational site Moravian Church Settlements, in 2024. Among the 35 sites, 29 are listed for their cultural significance, five for their natural significance, and one, St Kilda, for both. In addition, there are five sites on the tentative list. The UK has served on the World Heritage Committee once.