This paper studies the plastic deformation, localization and the necking behavior of polycrystalline dual phase (DP) steels, with different martensite volume fractions, and ferrite orientation distributions, through crystal plasticity finite element method. The grain structure of the full size micron-scale polycrystalline samples is built through Voronoi tesselation and the specimens are deformed under uniaxial loading condition. For the modelling of martensite phase J2 plasticity with isotropic hardening is employed while in randomly oriented ferrite grains the crystal plasticity theory works. The material parameters are identified with respect to uniaxial tensile experimental data using a fully periodic RVE with enough number of ferrite grains. The attention is focused on the effect of the martensite morphology and the ferrite orientation distribution on the formation of the shear bands and then the necking of the sample. (C) 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review line: Peer-review under responsibility of the 1st International Workshop on Plasticity, Damage and Fracture of Engineering Materials organizers.