Dry stone, sometimes called drystack or, in Scotland, drystane, is a building method by which structures are constructed from stones without any mortar to bind them together. Dry stone structures are stable because of their construction method, which is characterized by the presence of a load-bearing façade of carefully selected interlocking stones.

Dry stone construction is best known in the context of stone walls, traditionally used for the boundaries of fields and churchyards, or as retaining walls for terracing, but dry stone sculptures, buildings, bridges, and other structures also exist. The term tends not to be used for the many historic styles which used precisely-shaped stone, but did not use mortar, for example the Greek temple and Inca architecture.

The art of dry stone walling was inscribed in 2018 on the UNESCO representative list of the intangible cultural heritage of humanity, for dry stone walls in countries such as France, Greece, Italy, Slovenia, Croatia, Switzerland and Spain.