Langschlag is a municipality in the district of Zwettl, in the Austrian state of Lower Austria. It lies in the Waldviertel, the wooded northwestern quarter of Lower Austria, near the border with the Czech Republic.
The municipality is made up of a number of small villages and hamlets rather than a single dense town, a settlement pattern typical of this rural part of Austria. Its economy has traditionally been based on agriculture and forestry, reflecting the surrounding landscape of fields, meadows and woodland.