In this study, the dynamic behavior of two adjacent structures with fluid viscous damper (FVD) was investigated under the influence of earthquake and considering soil-structure interaction (SSI). Adjacent structures with FVD’s were analysed for three different soil types. The modelling and analysis were made in two-dimensional (2D) space by using ANSYS package program. Viscous boundary conditions were used on the boundaries of 2D soil model. The analyses results were obtained in terms of displacement, acceleration, and shear force. The effect of FVD was investigated using different connection types. The damping coefficient of FVD’s was assumed constant in all analyses. When the results of the analysis are examined, it can be seen that FVD’s are effective for seismic response. However, it is necessary to consider the soil-structure interaction. Significant different structural results were obtained between fixed support and three different soil types. For example, in the same model, while the top floor displacement may reduce in Soil Type I, the top floor displacement may increase in Soil Type II. At the end of the study, it was seen that there was no need to connect the FVD to all floors. It was found sufficient to connect a fluid viscous damper only to the top floor (1 FVD) or to the top and middle floor (2 FVD). FVD’s have no effect on buildings with the similar dynamic character. In the analysis for seismic control of adjacent buildings, the effect of soil-structure interaction should certainly be taken into account.