The main objective of earthquake engineering is to analyze, design and build a structure in such a way that the damage to the structure and its structural component during an earthquake is minimized. A large number of papers have focused to study the effect of irregular structures. Being inspired from the work contributed in the study on effect of earthquake on irregular shaped building this research work presents effect of plan and shape configuration on irregular shaped structures. Building with irregular geometry responds differently against seismic action. Plan geometry is the parameter which decides its performance against different loading conditions. This research work aims to evaluate the behaviour of irregularity (plan and shape) on structure under seismic effect. To workout the performance of structure, equivalent static analysis and response spectrum analysis has been adopted. For achieving this objective by using structural based software ETABS 19. Estimation of response such as: lateral displacement, storey drift, and base shear are carried out. Based on these parameters we have compared response of each model. Results are expressed in form of graphs and bar charts. From research it is observed that to minimize the effect of earthquake simple plan and configuration like regular shape must be adopted at the planning stage.