Structures resting on sloping ground are highly vulnerable to earthquakes due to irregularities in plan and elevation. Structures are often analysed under earthquake loadings, without considering the effect of soil–structure interaction (SSI). This practice is not advisable from practical point of view. In this present study, an attempt has been made to study the effect of slope angle variation for the structures resting on sloping ground, considering the base of the structures fixed as well as flexible (SSI). The analysis is performed in equivalent static force method (ESFM), response spectrum method (RSM), time history method (THM), nonlinear static method (NLSM) and nonlinear time history method (NLTHM). Results expose the criticality associated with increment of slope angle, with and without SSI consideration. Importance of considering SSI in seismic analysis is also revealed.