The traditional approach of seismic analysis of structures assumes that the structure is fixed at its base, omitting the effect of soil-structure interaction (SSI). The main objective of the present study is to create a three-dimensional Onshore Wind Turbine System that incorporates soil-structure interaction and to examine the onshore Wind Turbine behavior while taking the impact of SSI during seismic excitations into account. The results in terms of tip displacement, foundation settlement, tower base moments, and foundation stresses for the wind turbine resting on gravity foundation are compared and discussed. The results of ABAQUS numerical analysis showed that the inclusion of SSI has a significant impact on the foundation settlement and tower tip displacement on the seismic behavior of the wind turbine system. The research’s conclusions suggested that, when the SSI effect is taken into account, the seismic response in terms of the variance of foundation settlement and tower tip displacement increases in all three cases of earthquakes (El Centro, Bhuj, and Kobe). It is concluded that by adopting SSI in the analysis of gravity foundation, the tower tip displacement of the superstructure (tower) and foundation settlement can be maximized significantly.