In this paper progressive failure and activation of landslides in soils characterized by strain-softening mechanical behavior is numerically analyzed. As it is well known, the analysis of this phenomenon, from a computational point of view, presents many difficulties because the numerical procedures are often affected by lack of convergence, and because the solution may depend strongly on the mesh adopted. In order to overcome these numerical drawbacks, in the present study, finite numerical analyses of the stability of an ideal slope are performed by employing a non-local elasto-viscoplastic constitutive model. A yield function of the Mohr-Coulomb type is adopted, and the strain-softening behaviour of the soil is simulated by reducing the strength parameters at increasing deviatoric plastic strain. Four different versions of the same model are implemented, and the relative numerical results are critically compared.