The anisotropic etching behaviour of various crystalline silicon plates in an aqueous KOH solution was studied. Variations of the etch rate with the angle of cut related to singly-rotated plates have been determined and orientation effects in the out-of-roundness profiles related to various {hkO} sections have been analysed in terms of crystal symmetry. In addition, changes in the surface texture with crystal orientation were systematically investigated. All the experimental results furnished evidence for a dissolution process governed by the crystal orientation. A procedure has been proposed to derive the dissolution slowness surface from experiments starting from a tensorial representation of the anisotropic etching.