In highly populated cities, the close spacing of buildings often results in interaction effects, including structure–soil–structure interaction (SSSI) and seismic pounding (SP), which occur because of the limited gaps left between adjacent structures. In most seismic design and structural analyses, the soil–structure interaction effects are frequently ignored, even though the foundation–soil system can significantly alter the structural behaviour and response demands. Moreover, the vibration characteristics and seismic performance of a building cannot be considered independent from those of neighbouring structures. This study aims to examine SSI, SP and their combined effects (SSSI) on the performance of adjacent buildings. Three-dimensional finite element models were developed using ETABS program of single and three adjacent multi-story buildings with identical floor levels, supported on shallow raft foundations over soft soil. These models were analyzed and compared with fixed-base models to evaluate the influence of SSI. Furthermore, the seismic responses of the adjacent buildings under both fixed-base and soft soil conditions were compared with those of single-building models to assess the effect of SP. The combined influence of SSI and pounding (SSSI) was investigated by comparing the adjacent building model with SSI to the corresponding single-building fixed-base model. Seismic demands are evaluated using nonlinear time history (TH) analyses with nine earthquake records. Variations in period of vibration, story lateral displacement, story drift ratio, story shear force, story moment, story acceleration and pounding force are