Manganese oxides are of great scientific and technological relevance due to their wide range applications in catalysis, battery materials candidates, electrochemical electrodes, among others. Their properties are related to MnOx compounds chemistry-phase relationship to contain labile lattice oxygen and a particular density of Mn cations in a given oxidation state. For this reason, the growth of manganese oxides thin films on well-defined metal substrates has been widely explored in the literature. For this end, in this talk, I will discuss our own experimental findings on MnOx thin film growth on an Au(111) and Cu(111) substrates over a wide range of preparation conditions and film thicknesses investigated mainly by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). We will discuss the formation of MnO and Mn3O4 oxide phase and structure, and the possible consequences to its electronic properties depending on the film surface orientation and substrate.