An　experimental　and　numerical　investigation　into　the　flexural　buckling　behaviour　of　cold-formed　(CF)　high-strength　steel　(HSS)　square　hollow　section　(SHS)　members　is　reported　in　this　paper.　A　series　of　12　flexural　buckling　tests　were　conducted　on　S700　and　S900　CF　SHS　columns.　Finite　element　(FE)　models　were　developed　to　simulate　the　experimental　observations,　which　were　utilized　in　a　parametric　study　encompassing　a　broader　range　of　steel　grades　and　specimen　geometries.　Subsequently,　the　current　buckling　curves　in　European,　North　American,　and　Australian　codes　was　evaluated　through　reliability　analyses.　Meanwhile,　the　effective　width　method　(EWM)　and　the　modified　generalized　slenderness-based　resistance　method　(GRSM)　were　compared　for　slender　cross-sections.　According　to　the　results　of　reliability　analyses,　the　modified　buckling　curves　were　proposed　for　CF　HSS　SHS　columns.