We have carried out synchrotron radiation measurements both from valence states and core levels from Si(111)–Cu, Si(111)–Ag, Si(111)–Au, Si(111)–Pd interfaces before and after exposure at room temperature to 30×106 L of oxygen and we compare the results with those for the oxidation of Si(111). In all cases the oxygen interacts with Si and not with the metal, and the Si reaction rate is strongly increased with respect to that of Si(111). The strongest oxidation enhancement is obtained with Cu and Pd. In the noble metal case the interaction with oxygen produces the overgrowth of a SiO2‐like phase having a Si 2 p chemical shift of ∠3.8 eV as opposite to Si(111) which cannot be oxidized to SiO2 in these conditions. Moreover, in the Si–Pd case the oxidation number is lower and the chemical shift is ∠2.3 eV. We discuss the relevance of the results both in terms of the structure of the interface and of the nature of the chemical interaction between Si and d metals.