The effect of thermal stresses and deformations on the performance of a structure was generally not well treated in previous EBCS design codes. This study aims to investigate the responses of two-dimensional structural steel frames subjected to high temperature and compare the results with the same structures at ambient temperature. The change in temperature causes a material to expand and if this expansion is restrained, stresses are induced affecting the performance of the structure. The force generated by thermal strains is very large, depending on the amount of the change in temperature, and its ignorance may lead to unsafe design. Structural capacity of building can be affected by fire in two ways: either by reduction of overall structural capacity due to degradation of their engineering properties resulted from prolonged exposure of structural components to elevated temperatures or local and global instability due to development of internal forces or axial deformations in structural members due to plastic and creep strains or buckling due to restraint of thermal expansion. In this study analysis of ten story and five bay steel frame with different types of support restrain conditions subjected to ISO 834 fire loading have been conducted and the responses are compared with those from the same frame without fire loading. The analyses were performed using commercial finite element software Abaqus by including the effects of geometric nonlinearity and temperature dependent nonlinear material behavior. The results from this thesis shows a significant change in structural response of beam and column frame elements due to elevated temperature. This research is a preliminary study to show a significant difference in response due to fire loading. It is hoped that the study will initiate designers and scholars to study further the effect of fire on the behavior of complex steel frame members as well as the connection.