Slender columns exhibit instability under compression, which causes buckling. Prestressed stayed system can be used to improve the load carrying capacity of these columns. In this study, three-dimensional prestressed stayed column was investigated through the use of commercially available finite element software-ABAQUS. Although many numerical studies into the buckling behavior of stayed columns exist, these have mainly focused on two-dimensional (2D) systems. In order to fully understand the behavior of these structural systems, three-dimensional (3D) numerical studies are essential. In this work, the buckling behavior of three-dimensional prestressed stayed columns was investigated through linear perturbation method. The critical buckling loads and modes of four-branch and three-branch columns were investigated. The effect of varying the cross-arm length on the buckling load of the four-branch column was also investigated and compared with the theoretical values. It was found that the theoretical buckling loads reported in previous research with 2D systems were conservative and largely underestimated the buckling capacities of prestressed stayed columns. Furthermore, it was observed that transition point from the symmetric to antisymmetric buckling mode occurs at a higher value of cross-arm to column length ratio for the 3D prestressed stayed columns compared to the 2D model.