A clamping device for clamping a flat material test sample while a material test is carried out is provided. The clamping device includes a substantially cylindrical clamping part, from the free end of which there extends a receiving slot for receiving the material test sample, a pressure ring surrounding the clamping part in the region of the receiving slot, and a pressure sleeve provided between the clamping part and the pressure ring, the pressure sleeve is formed and actuable such that, under radial expansion, it connects the clamping part and the pressure ring together and clamps the material test sample held in the receiving slot.