The　critical　current　(Ic)　of　commercial　rare-earth　barium　copper　oxide　(REBCO)　tapes　is　generally　assumed　to　exhibit　isotropic　behavior　with　respect　to　the　magnetic　field　angle　applied　within　the　tape＇s　basal　plane　(in-plane).　This　paper　investigates　the　field　angle　dependence　of　critical　current,　both　in-plane　and　out-of-plane,　for　commercial　REBCO　tapes　manufactured　by　SuperOX,　under　fields　ranging　from　0　T　to　8　T　at　20　K.　Remarkably,　the　in-plane　field　angle　dependence　of　Ic　shows　significant　anisotropy,　with　the　minimum　Ic　no　longer　occurring　at　the　traditional　90　degrees　(parallel　to　the　ab-plane),　but　instead　shifting　to　approximately　130　degrees,　a　phenomenon　reported　for　the　first　time.　This　novel　anisotropic　in-plane　field　angle　dependence　of　Ic　can　substantially　affect　the　performance　of　toroidal　field　magnets　for　compact　tokamak　fusion　devices.　Simulations　indicate　that　considering　versus　neglecting　the　anisotropic　in-plane　field　angle　dependence　of　Ic　can　lead　to　Ic　variations　of　up　to　19.58%　within　the　D-shaped　coils　of　the　toroidal　field　magnets.　The　locations　of　maximum　deviation　vary　across　different　double-pancake　coils　within　the　D-shaped　winding　packs.　This　study　highlights　the　complexity　of　Ic　distribution　in　toroidal　field　magnets　for　compact　fusion　applications,　urging　further　consideration　of　anisotropic　in-plane　field　angle　dependence　of　Ic　of　commercial　REBCO　tapes　in　fusion　magnet　design.