In this thesis, I present my research work on epitaxial thin films of LaNiO3 and SrMoO3, investigated by angle-resolved photoemission spectroscopy (ARPES), which yields a direct measurement of the interacting electronic structure. Thin films of the correlated transition-metal oxide LaNiO3 undergo a metal-insulator transition when their thickness is reduced to a few unit cells. Our high-resolution data on films grown by in-situ sputter deposition reveal a previously unreported drop in the electronic mean free path as the film thickness is reduced below 5 unit cells, which can explain the universally reported absence of quantum-well states in ARPES experiments on nickelate thin films. In the insulating state, the coherent quasiparticle peak is strongly suppressed, without a clear gap. Single-crystal bulk SrMoO3 exhibits the lowest room-temperature resistivity of any known perovskite transition-metal oxide and has therefore attracted considerable interest for its possible applications in oxide-electronics. Our ARPES data from SrMoO3 thin films grown by sputter deposition and pulsed-laser deposition show a Fermi surface and band structure in agreement with electronic-structure calculations. The electronic self-energy of SrMoO3, determined from a comparison to a realistic density-functional theory (DFT) model, is significantly smaller than for the particle-hole-symmetric ruthenate SrRuO3 and agrees with dynamical mean-field theory (DMFT) calculations. We show that the higher mass enhancement in ruthenates can be attributed to their larger density of states at the Fermi level.