Steel-concrete composite (SCC) girders are becoming more popular in the construction industry as they facilitate speedy construction and have a higher span-to-depth ratio. Simply-supported SCC girders are preferred over continuous girders for railways over bridges and flyovers to avoid traffic disturbance during construction or maintenance work. Due to its slender cross-section, the SCC girder is vulnerable to serviceability criteria of deflection. The existing literature shows that additional stresses generated due to the temperature gradient effect would lead to an increment in the deflection of the SCC girder. Various codal provisions have described different empirical temperature gradient models acting on SCC girder. The present study compares the thermal stress distribution across the cross-section and deflection of the SCC girder due to the temperature gradient models provided in different codal provisions. The proposed methodology offers a computationally efficient alternative to 3D finite element models, with less than 15% difference in thermal stress and deflection predictions, suitable for daily design practices.