In the article, results of theoretical calculations of the piezoresistance characteristics of impurity germanene nanoribbons (NR) of the “arm-chair” type with donor defects with various concentrations uniformly distributed in the crystal lattice of the nanomaterial have been presented and analyzed. Arsenic atoms were used as donor impurities. Investigations of the NR’s band structure were carried out in the frameworks of the Hubbard’s and Anderson’s models. The computation of the main characteristic of the piezoresistance effect, i.e., the longitudinal component of the elastic conductivity tensor was carried out using the Green's function method within the framework of the same theoretical models. An analysis of the dependence of this characteristic on the tensile and compressive strains, the concentration of impurities and the nanoribbon width were carried out.