End-plate bolted connections are among the most spread-out connections used in steel structures. Understanding their behavior depends on a combination of experimental and numerical analyses, along with parametric studies. This approach provides precise information about the properties of these connections. Two full-scale joint specimens were tested, including one with two bolts 2b and one with four bolts per horizontal row 4b. This study recorded and presented the force versus displacement (F-Δ) curves, the corresponding moment versus rotation (M-φ) curves and the failure mode. These results demonstrate that the type 4b connection exhibited a higher moment resistance and greater initial rotational stiffness. The ABAQUS FE package was used to develop the Finite Element (FE) models, considering material, geometrical and contact interaction between components non-linearities. The experimental and numerical results were compared based on the force-displacement curves and observed failure modes, showing strong agreement allowing their further use in the more detailed components assessment. So, based on the data gathered from the experiments and finite element (FE) analyses, a parametric study was conducted on extended end-plate bolted beam-column connections under monotonic loading. This study examined the influence of various parameters, such as end-plate thickness, bolt diameter, and column web stiffeners' impact on both analyzed connection types, 2b and 4b. The results of this study show that the thickness of the end-plate should be moderated and in line with the diameter of the bolt; also, the presence of the web stiffeners is mandatory.