<p>Employing base isolators is one of the effective approaches of achieving seismic resilience in buildings. In order to gain a comprehensive understanding of the seismic performance of base-isolated buildings across the spectrum of seismic intensities, the assumption that the superstructures of base-isolated buildings remain linearly elastic is inadequate. For this reason, the present study proposes a reduced-order model for base-isolated buildings, accounting for possible inelastic excursions of superstructures due to extreme earthquakes or near-fault pulse-like (PL) ground motions. The proposed reduced-order model, called the base-isolated generalized building model (GBM), consists of two sticks, which deform in pure shear and pure flexural types, respectively. As a numerical verification, this study examined a base-isolated three-story reinforced concrete building and a base-isolated nine-story steel building subjected to two near-fault PL ground motions, resulting in peak inter-story drift ratios (IDRs) of 2.4% and 4.8%, respectively. The proposed reduced-order model satisfactorily estimated the peaks and phases of the displacement and acceleration histories of the two buildings under the two earthquakes, as well as the distribution of plastic hinges along building heights. An additional ensemble of 19 ground motion records was applied to the base-isolated nine-story building, with the peak IDR ranging from 0.92% to 3.91%. The mean peak IDRs obtained from the complete finite element model and the base-isolated GBM were 1.96% and 2.11%, respectively. In addition, the maximum absolute errors of the estimated mean peak values of base shear, isolator displacement, and isolator acceleration were 2.10%, 22.94%, and 6.44%, respectively.</p>