In this work, elasto-plastic stress analysis of a Single Lap Joint (SLJ) subjected to bending moment was investigated using 2D non-linear Finite Element Analysis (FEA). The SLJs, consisting of hardened steel as the adherend bonded by two adhesives, one stiff and one flexible, with very different mechanical behaviors were analyzed. In order to determine the effect of geometrical parameters on the performance of the SLJs, four different adherend thicknesses and overlap lengths for each adhesive were used. For verification of the analysis, the FEA results were compared with experimental results. It was observed that there was a significant effect of adherend thickness on the strength of the joint with both adhesives. However, the load carried by the SLJ with the flexible adhesive increased with increasing overlap length.