External　bonding　(EB)　of　fiber-reinforced　polymer　(FRP)　laminates　has　emerged　as　a　popular　method　to　strengthen　reinforced　concrete　(RC)　structures.　The　premature　failure　of　these　structures　is　induced　by　debonding　across　the　FRP-concrete　interface.　The　mixed-mode　debonding　of　the　FRP-concrete　interface　will　be　analyzed　by　a　cohesive　zone　model　(CZM)　derived　from　the　modified　Mohr-Coulomb　strength　criterion.　The　partial　derivatives　of　the　normal　and　tangential　stresses　that　concern　the　interfacial　separations　will　be　presented　in　this　study,　which　will　facilitate　the　program　coding　to　implement　the　proposed　model.　The　coupled　mixed-mode　CZM　provided　a　detailed　description　of　the　initial　debonding　and　propagation　of　the　FRP-concrete　interface　through　a　full　range　mixed-mode　debonding　process.　Parametric　studies　will　be　conducted　to　provide　a　clear　understanding　of　the　mixed-mode　loading-dependent　debonding　process　of　the　FRP-concrete　interface.　The　proposed　model　could　be　utilized　to　effectively　and　efficiently　analyze　the　mixed-mode　debonding　of　the　FRP-concrete　interface.　©　2021　American　Society　of　Civil　Engineers.