In this study, we report influence of exfoliated graphene nanoplatelets on the flame retardancy and thermal properties of hybrid kenaf flour graphene nanoplatelets polypropylene nanocomposites. Mass loss calorimeter, Limiting oxygen index and Universal laboratories-94-V fire test instruments were employed for flammability investigations. Fire results revealed improved flame retardancy of composites through enhanced fire performance index, prolonged time to ignition and reduced fire growth index. Heat release rate, peak heat release rate, time to peak heat release rate, mass loss rate and total heat release rate essential for the protection of human lives and properties during actual fire scenario were enhanced. Incorporation of graphene nanoplatelets improved flame retardancy of the materials. The GNP char structure improved flame retardancy by acting as heat shield and protective layering on surface of the materials thereby hindering transfer of oxygen and heat from the fire region to the underlying matrix while simultaneously inhibiting the penetration of flammable gases from underlying matrix to the combustion zone thereby cutting-off the fire track.