Soil–structure interaction (SSI), which characterizes the dynamic interaction between a structure and its surrounding soil, is of great significance to the seismic assessment of structures. Past research endeavors have undertaken analytical, numerical, and experimental studies to gain a thorough understanding of the influences of SSI on the seismic responses of a wide array of structures, including but not limited to nuclear power plants, frame structures, bridges, and spatial structures. Thereinto, large-span spatial structures generally have much more complex configurations, and the influences of SSI may be more pronounced. To this end, this paper aims to provide a state-of-the-art review of the SSI in the seismic assessment of large-span spatial structures. It begins with the modelling of soil medium, followed by the research progress of SSI in terms of numerical simulations and experiments. Subsequently, the focus shifts towards high-lighting advancements in understanding the seismic responses of large-span spatial structures considering SSI. Finally, some discussions are made on the unresolved problems and the possible topics for future studies.