Enhancing photon tunneling probability is the key to increasing the near-field radiative heat transfer between two objects. It has been shown that hexagonal boron nitride (hBN) and graphene heterostructures can enable plentiful phononic and plasmonic resonance modes. This work demonstrates that heterostructures consisting of a monolayer graphene on an hBN film can support surface plasmon–phonon polaritons that greatly enhance the photon tunneling and outperform individual structures made of either graphene or hBN. Both the thickness of the hBN films and the chemical potential of graphene can affect the tunneling probability, offering potential routes toward passive or active control of near-field heat transfer. The results presented here may facilitate the system design for near-field energy harvesting, thermal imaging, and radiative cooling applications based on two-dimensional materials.