The current study is concerned with the structural response of typical semi-rigid steel beam-to-column joints. In particular, the behaviour of bolted cleat angle connections is investigated under different loading conditions, both monotonic and cyclic loading being considered. Besides, aiming at assessing the susceptibility of the analysed connection typology to low-cycle fatigue, the latter has been referred to both constant and variable amplitude deformations. Therefore, 15 full-scale tests have been carried out by comparing the performance of specimens with reference to three different sizes of column member as well. Obtained results are provided in terms of moment-rotation relationship, dissipated energy and strength degradation per cycle. As expected, outcomes show that the main sources of inelastic deformation are located into cleat angles, which constitute the most influential component. As a consequence, the column size has a limited effect on the whole hysteretic response of the joint, while results appear to be strongly dependent on the applied deformation history.