Several structures have employed steel plate shear walls (SPSWs). It might cause excessive lateral drift and substantial seismic demands on vertical boundary elements (VBEs). A sensible workaround for SPSW systems is to install an outrigger as a dissipated system in place of the adjacent bay of the SPSWs. This will disperse some of the overturning forces to the adjacent columns, thereby reducing lateral drifts and seismic demand on the VBEs. Nonlinear time history studies are performed for 12- and 20-story free-standing SPSWs with different wall bay width-to-depth ratios and SPSWs combined with Buckling restrained brace outrigger (BRB-O). The effectiveness of the BRB-O on the overall seismic behavior is investigated. These elements are placed in single and double BRB-Os at various locations along the wall. The findings indicated that adding BRB-O significantly reduces lateral responses. Positioning a single BRB-O in the stories near the middle height of the SPSW or above (especially at ¾ of the structure's height from the base) will improve its stiffness more than that placed in the below stories. The most effective way to position the double BRB-Os is to place one at the top and the other at a high level of the structure's height, particularly if the other outrigger is positioned at ¾ of the structure's height. It is more effective to add double BRB-Os where one is located at the top story rather than between inter-stories. The width-to-depth ratio of the web panel and outrigger width influences the decrease in the VBE's axial forces.