This paper proposes formulations for predicting lateral load-bearing capacity of two types of composite shear wall (CSW) systems, which consist of a steel frame and a reinforced concrete (RC) plate attached to one side using bolts. Due to the high out-of-plane stiffness of the RC plate, it can effectively provide out-of-plane constraint to prevent out-of-plane deformation of the steel plate in CSW systems. However, in traditional CSW systems, direct contact between the RC plate and the frame often results in crushing at the former under seismic loading, thereby providing insufficient restraint against out-of-plane deformation of the steel plate. In contrast, the innovative CSW system with a gap maintained at the steel frame and RC plate exhibited superior seismic behavior than its traditional counterpart. While previous studies have investigated cyclic behavior and parameter effects of CSW systems, there remains a gap in evaluating their lateral strength. The proposed formulations show a mean distinction among theoretically determined and actual lateral load-bearing capacity less than three percent.