Short Fibre Reinforced Composites (SFRCs) have high specific properties. Also, fabrication processes of these materials are efficient both time-wise and cost-wise. As a result, a trend of increasing usage of SFRCs is observed in different industries. Many microstructural properties, such as fibre volume fraction; fibre orientation distribution; fibre geometrical aspects etc., affect the macroscopic behaviour of these materials. Hence, to have an accurate structure-property relationship for these materials, it is crucial to take these microstructural properties into account in the modelling process. In this study, we have developed a two-step non-linear elasto-plastic micro-mechanical model for SFRCs. In the first step, a number of elasto-plastic Finite Element (FE) computations are conducted on a Unit Cell (UC) that is essentially a single fibre surrounded by matrix material. Based on these FE results, a surrogate constitutive model is calibrated. This calibrated surrogate model is then subsequently used in a second Orientation Averaging (OA) step, following Advani and Tucker [1]. Here, in addition to widely used interaction assumptions such as Voigt and Reuss that provide upper and lower bounds, a self-consistent interaction is also developed and evaluated. The developed model is not only capable of accurate predictions but also has a considerably better computational performance compared to computational homogenization approach. To facilitate practical and/or industrial use, a coupled multi-scale model is developed using FEM (at the macro-scale) and the micro-mechanical model (at the micro-scale). In order to reduce the computational cost of this model, a Bazant integration scheme [2] is adopted in the OA step. In addition, a more efficient integration approach for the calculation of the Eshelby tensor (for the self-consistent interaction) is employed. As a result, a remarkably improved computational enhancement is achieved in the coupled multi-scale model, and full-scale analysis of structures/specimens with a variety of micro-structural properties is enabled.