Allentsteig is a municipality in the district of Zwettl, in the state of Lower Austria, Austria. It lies in the Waldviertel, the wooded northwestern quarter of Lower Austria, a rural region of rolling hills, forests and small towns.
The town is best known for the extensive military training area that bears its name, the Truppenübungsplatz Allentsteig, one of the largest such facilities in Austria. Established in the late 1930s, the training ground occupies a large tract of land around the town and has shaped the area's character and economy for decades.
Allentsteig itself is a small, quiet settlement that serves as a local administrative and service centre for the surrounding countryside. Its setting in the Waldviertel places it within reach of the region's characteristic landscape of woods, ponds and historic small towns, and it is connected to the wider area by road and rail links through the Zwettl district.