'Megalithic art refers to the use of large stones as an artistic medium. Although some modern artists and sculptors make use of large stones in their work, the term is more generally used to describe art carved onto megaliths by prehistoric peoples. Other forms of prehistoric art such as cave paintings and mobiliary art appear to have served different purposes to megalithic representations which are often highly abstract and serve no obvious purpose. Megalithic art can include petroglyphs although not all petroglyphs constitute megalithic art as they are often carved in natural rock surfaces such as cave walls rather than on purposefully placed megaliths.

Archaeologists have found numerous examples of artistic expression at megalithic monuments from prehistoric societies although they represent only a minority of the total number of sites. Some are in the context of funerary monuments whilst others are less comprehensible. It has been suggested they play wider ritual or social roles, to be representations of calendars for example, or to be attempts to recreate the effects of psychedelic drugs.

Weathering and modern vandalism have affected many sites although many new sites have been identified in recent years

Megalithic art in the British Isles

Megalithic art in the British Isles seems to have began in the Neolithic and continued into the Bronze Age. Cup and ring marks have been seen at numerous sites (both on megaliths and natural rock surfaces) including the capstones at Newgrange. More elaborate art was created at the Bryn Celli Ddu chamber tomb in Wales. Carvings of tools onto some of the trilithons at Stonehenge may date to the Bronze Age.

Megalithic art in Spain

Similar cup and ring marks and petroglyphs are known in north western Spain.