This work presents an analytical approach for solving the nonlinear mechanical response of hybrid glass fibers reinforced graphene polymer composite materials. Two-scale homogenization technique derives the effective properties of the composite. At the first scale, the properties of a 2-phases graphene/polymer composite are obtained by accounting for the J2 plasticity coupled with the “Lemaitre–Chaboche” ductile damage model. An interfacial imperfection between the fillers and the matrix is considered through the linear spring model (LSM). At the second scale, the modeling of the 3-phases glass fibers/graphene/polymer composite combines the 2-phases composite as a matrix phase in which are embedded the glass fibers. For both scales, a modified Mori–Tanaka scheme derives the effective properties. Numerical results, obtained for a thermoplastic PA6 matrix, are compared with the multistep method of Digimat software. Finally, a tension–torsion test shows that the imperfection at the fibers/polymer interface is the driven parameter to weaken mechanical responses in the shear direction.