There is a strong relationship between the architectural design and theearthquake safety of the building. So architects are advised to design regularand symmetric structures, that if the distribution of floor masses and thedistribution of load- resisting elements are not symmetric with respect to some orthogonal axes, the buildings are considered asymmetric. This studyaims to investigate the effect of shear wall arrangement, and the shear wallthickness, and the different ground accelerations on the performance ofasymmetric plan structures to seismic loads. A twenty story asymmetricplan structure with four openings in its floor slab is analyzed under seismicloads. Eight models are investigated where the differences between themwere according to location and arrangements of shear walls and the places ofthe opening. The software used here is ETABS program. Thirty fiveearthquake records were used as ground accelerations The thickness of shear walls was changed from 0.25 to 0.60 m 250.3, 0.4, 0.5, and 0.60) to get the effect of these increments on theperformance of the structure. As a result of the proposed study, it isconcluded that plans which have shear walls allocated on the outer edgesbehave more acceptable than that haven’t shear walls on the outer edgeswhere the first ones have minimum displacements and minimum interstorydrifts. The increasing in shear wall thickness decreases the displacement ofthe top story as so as the interstory drift while it increases the torsion andbase shear. As an exception for some earthquakes the increment in shearwall thickness causes increment in top story displacement due to theadjacent of the structure fundamental frequency and frequency content ofthese earthquakes. A comparison is carried out between the results produced