A Non-Equilibrium Molecular Dynamics Model is Developed to Investigate How a Thin Film Confined between Two Dissimilar Solids Affects the Thermal Transport Across the Material Interface. for Two Highly Dissimilar (Phonon Frequency Mismatched) Solids, It is Found that the Insertion of a Thin Film between Them Can Greatly Enhance Thermal Transport Across the Material Interface by a Factor of 2.3 If the Thin Film Has One of the Following Characteristics: (1)a Multi-Atom-Thick Thin Film of Which the Phonon Density of States (DOS) Bridges the Two Different Phonon DOSs for the Solid on Each Side of the Thin Film; (2)a Single-Atom-Thick Film Which is Weakly Bonded to the Solid on Both Sides of the Thin Film. the Enhanced Thermal Transport in the Single-Atom-Thick Film Case is Found Mainly Due to the Increased Inelastic Scattering of Phonons by the Atoms in the Film. However, for Solid-Solid Interfaces with a Relatively Small Difference in the Phonon DOS, It is Found that the Insertion of a Thin Film May Decrease the Thermal Transport. © 2011 IOP Publishing Ltd.