Abstract <p>The electroplastic effect is a sharp decrease in the deformation stress of metals under the action of an electric pulse. The mechanism of the electroplastic effect is still unclear. There is no explanation for the accumulated experimental data. In this paper, we propose a new mechanism of the electroplastic effect in metals, which is governed by athermal displacements of pinned dislocations during nonadiabatic Landau–Zener transitions of atoms in an open system of nuclei and electrons. The electric pulse action causes additional displacements of atoms in the specimen volume, increases the velocity of athermal displacements of dislocations and the plastic strain rate, which leads to a drop in the deformation stress. An explanation is provided for the experimental pattern of electroplastic deformation.</p>