The epitaxial growth of aluminum [111] by sputtering deposition on Ni80Fe20 [111] has been demonstrated, despite the large 12.2% lattice mismatch in this system. The absence of high angle grain boundaries in epitaxial films would lead to thinner, smoother and more uniform barrier layers in spin-dependent tunneling junctions. The strain evolution was monitored by in-situ reflection high-energy electron diffraction, and grazing incidence X-ray scattering diffraction was used to verify the epitaxial growth. The aluminum film after natural oxidation was extremely smooth, with an rms roughness of 0.2 nm as measured by atomic force microscopy.