This paper presents an experimental and a FE analysis of the compressive behavior of slender section columns with and without stiffeners. A series of tests was performed on specimens with different overall heights and different number of stiffeners. A nonlinear three-dimensional FE model was developed using ANSYS program. The efficiency of the nonlinear FE model was verified and a parametric analysis was performed considering variation of number of stiffeners, values of web depth-to-thickness ratio, flange-tothickness ratio, and slenderness ratio. The load carrying capacity of steel columns with large web-tothickness ratio is noticeably enhanced up to 34% by increasing number of web stiffeners. Initial imperfection during fabrication should be well controlled and should be carefully considered in the FE modelling. Post local buckling strength of the sections is more sensitive to web width–thickness ratio than flange width–thickness ratio.