Heart of Neolithic Orkney refers to a group of Neolithic monuments found on the Mainland, one of the islands of Orkney, Scotland. The name was adopted by UNESCO when it proclaimed these sites as a World Heritage Site in 1999.

The site of patrimony currently consists of four sites:

1. Maeshowe – a unique chambered cairn and passage grave, aligned so that its central chamber is illuminated on the winter solstice. It was looted by Vikings who left one of the largest collections of runic inscriptions in the world.
2. Standing Stones of Stenness – the four remaining megaliths of a henge, the largest of which is 6 metres (19 ft) high.
3. Ring of Brodgar – a stone circle 104 metres in diameter, originally composed of 60 stones set within a circular ditch up to 3 metres deep and 10 metres wide, forming a henge monument. It has been estimated that the structure took 80,000 man-hours to construct.
4. Skara Brae – a cluster of eight houses making up Northern Europe’s best-preserved Neolithic village.

Ness of Brodgar is an archaeological site between the Ring of Brodgar and the Stones of Stenness that has provided evidence of housing, decorated stone slabs, a massive stone wall with foundations, and a large building described as a Neolithic "cathedral". Although it is not part of the World Heritage Site, the Ness of Brodgar "contributes greatly to our understanding of the WHS" according to Historic Scotland, which manages most of the site.

In 2008, UNESCO expressed concern about plans by the local council to "erect three large 72 metres wind turbines to the north-west of the Stones of Stenness and the Ring of Brogdar" that might have a potential negative impact on the site.​