The paper investigates the thermal transport properties of monolayer graphene exfoliated on a silicon dioxide (SiO₂) support. Despite the substrate interaction, the room-temperature thermal conductivity (κ) of the supported graphene remains high, reaching about 600 watts per meter per kelvin (W/mK), which is higher than that of common thin-film electronic materials but lower than the 3000 to 5000 W/mK reported for suspended graphene. The authors attribute the lower κ to phonon leakage across the graphene-support interface and strong interface scattering of flexural modes, which significantly contribute to κ in suspended graphene. Quantum mechanical calculations reveal that the flexural modes play a crucial role in the thermal conductivity of suspended graphene, but their contribution is reduced in supported graphene due to stronger substrate scattering. The study provides insights into the thermal transport behavior of graphene supported on substrates, highlighting the importance of considering substrate interactions in the design of heat dissipation systems in nanoelectronics.The paper investigates the thermal transport properties of monolayer graphene exfoliated on a silicon dioxide (SiO₂) support. Despite the substrate interaction, the room-temperature thermal conductivity (κ) of the supported graphene remains high, reaching about 600 watts per meter per kelvin (W/mK), which is higher than that of common thin-film electronic materials but lower than the 3000 to 5000 W/mK reported for suspended graphene. The authors attribute the lower κ to phonon leakage across the graphene-support interface and strong interface scattering of flexural modes, which significantly contribute to κ in suspended graphene. Quantum mechanical calculations reveal that the flexural modes play a crucial role in the thermal conductivity of suspended graphene, but their contribution is reduced in supported graphene due to stronger substrate scattering. The study provides insights into the thermal transport behavior of graphene supported on substrates, highlighting the importance of considering substrate interactions in the design of heat dissipation systems in nanoelectronics.