Single-crystal (0 0 0 1) GaN samples have been deformed with a Vickers indenter at room temperature using loads in the range from 0.02 to 4.90 N. Dislocations and cracks at the indentations were examined by means of scanning electron microscopy, cathodoluminescence, light microscopy and transmission electron microscopy. Geometrical relations could be found between the dislocation arrangement, cracks and the orientation of the indenter. The orientation of the indenter has only a slight effect on the dislocation pattern, but the crack system is predominantly determined by the symmetry and the orientation of the indenter.