Nowadays, using the Eurocode 3 component method, it is possible to evaluate the rotational stiffness and moment capacity of semi-rigid joints when subject to pure bending. However, this component method is not yet able to calculate these properties when, in addition to the applied moment, an axial force is also present. The main aim of this paper is to propose a mechanical model for semi-rigid end-plate beam-to-column joints including the axial force versus bending moment interaction. This paper also presents a detailed description of the numerical results that were generated and validated against experiments and analytical data.