Nowadays many techniques have been developed to make buildings taller and more efficient. Moreover, if unsymmetrical tall buildings are considered, the stability of structure plays a vital role and these are majorly effected by the lateral loads like wind and earthquake. In order to resist from lateral loads, different structural systems have been followed practically like bracing system, outrigger system, dia grid, hexa grid systems. This paper deals with the use of outrigger system for unsymmetrical tall building of 30 storey and its Comparision with the same building without outrigger system. This paper also emphases on determining the exact position of outrigger in tall buildings. Also, in the second case, keeping the height of the building same as that of the conventional building the floor areas are increased by reducing the number of interior columns with and without outrigger system and the stability is checked. The results reveal the ideal position of outrigger at top position and other at 0.5 times the height of the building. and with the use of outrigger system the displacement is reduced to 26.69% which improves the stiffness and efficiency of unsymmetrical building. © IJSTR 2020.