AbstractSteel plate shear walls (SPSW) have been increasingly applied in structures as a lateral load resisting system. SPSW systems utilize thin unstiffened plates as the infill between boundary members. Infill panels are very slender elements and buckle under low lateral loads due to which SPSW relies on the post‐critical tension field action of the infill panel. Such load transfer mechanism has two downsides: a) significant transverse forces are exerted on the boundary elements, particularly columns; b) load bearing capacity of the tension infill panel after yielding is lower than yielding of the panel in shear. In order to preclude these shortcomings relatively new vertical stabilization systems, termed composite plate shear walls (CPSW), were developed where stiffening of the infill panel using reinforced concrete plate was introduced. However, lack of research on CPSW systems led to creation of structural building codes which adopted requirements prescribed for SPSW. Experimental and numerical research has been conducted on CPSW. Three specimens, with varying column flexural stiffness, were tested. The obtained results show less prominent column “pull‐in” when compared to SPSW. The results were assessed comparing stiffness, resistance and ductility between the above‐mentioned systems. Finally, the experimental results were used to calibrate numerical models. Afterwards, the obtained numerical results served for more detailed comparison of behaviour between SPSW and CPSW.