The Buckling-Restrained Braced Frame (BRBF) is used as a building’s primary seismic-load resisting system having full, balanced hysteretic behavior in both compressive behavior and tensile behavior. The multistory X configuration is recommended due to its benefit, reducing unbalanced vertical loads on the frame beams and offering the chance to more effectively distribute yielding across several stories. The purpose of this study is to investigate the seismic performance of multistory X-BRBF applied in reinforced concrete building using nonlinear response history analysis. The prototype building is a typical 8-story office building having five bays with span length of 6 m. The analysis results show that the first plastic hinges occur in the bracing members, as the braces are intended to dissipate the seismic energy. As the ground motion duration increases, the plastic hinges are also formed in both ends of the corner columns of the lowest story. The possible reason is that, the corner columns are designed to sustain the interaction of the axial force and the uniaxial bending caused by the unbalanced loads from the adjusted brace strengths only for one direction. However, the corner columns are shared by the intersecting braced frame. During the ground motion excitation, the corner columns might experience axial forces from both directions and biaxial moment due to the moment from orthogonal directions. At the end of ground motion excitation, the plastic hinges are formed in all BRBs and both ends of corner columns of the lowest story.