This paper investigates experimentally the efficiency of thermal insulation layers in preserving the flexural capacity of fiber-reinforced polymer (FRP) reinforced concrete beams subjected to elevated temperature. FRP rebars are innovative alternatives to conventional steel reinforcement rebars in reinforced concrete structures, however, there is a need to identify the performance of those beams under fire scenario. Four concrete beams reinforced by different FRP rebars are investigated under elevated temperature exposure up to 800oC for two hours, two of those beams are thermally insulated by 25 mm thick of thermal insulation layer of perlite mortar. Experimental tests showed that the insulation layer enhanced the flexural performance of the concrete beams compared to the uninsulated beams. Moreover, the thermally insulated beams showed that the main failure mode is concrete crushing at top substrate of tested beams as recommended by the design guidelines. The thermal progression, failure load, failure mechanism and mid-span deflection of the tested beams are presented and discussed.