Steel　rebar　buckling　is　an　important　failure　mode　in　reinforced　concrete　(RC)　columns.　Fiber-reinforced　polymer　(FRP)　composites　provide　an　effective　mean　that　can　restrain　or　delay　longitudinal　rebar　buckling.　To　accurately　predict　the　strength　and　ductility　of　FRP-strengthened　rectangular　RC　columns,　it　is　necessary　to　accurately　evaluate　the　interactions　between　FRP　confinement　and　steel　reinforcement　buckling　behavior　at　as　any　loading　levels　as　possible.　This　paper　proposed　a　composite　beam　model　and　a　tension-bending　beam　model　to　evaluate　the　lateral　support　stiffness　of　FRP-wrapped　concrete　cover　on　steel　reinforcement　in　the　corner　regions　and　flat　sides　of　rectangular　columns.　Then,　the　whole　stress-strain　curves　for　reinforcing　bar　buckling　behavior　considering　the　lateral　support　of　FRP　jackets　can　be　obtained　and　validated　with　the　existing　test　database.　For　FRP-strengthened　rectangular　RC　columns　under　monotonic　axial　compression,　the　overall　load-bearing　capacity　of　RC　columns　can　be　determined　by　summarizing　axial　loads　sustained　by　FRP-confined　corresponding　plain　concrete　(PC)　columns　and　the　load　contribution　of　steel　rebars　considering　FRP　lateral　support.　The　accuracy　of　the　proposed　method　is　demonstrated　by　comparing　theoretical　predictions　with　test　results.　This　calculation　method　can　accurately　predict　the　strength　and　ductility　of　FRP-wrapped　rectangular　columns　within　a　20%　variation　margin,　which　provides　a　reliable　basis　for　the　design　of　concrete　structures.