Abstract The oxidation of the α and β phases of brass is studied between 293 and 673 K by means of prompt nuclear reactions, resonant alpha backscattering, and X-ray photoelectron spectroscopy. The oxide layer thickness is obtained from the nuclear methods whereas XPS provides the surface composition and a depth profile of the first few atomic layers. The Zn and Cu oxides are distributed inhomogeneously, and a dependence on phase and sample treatment is observed. In particular, there is an inversion of the oxidation rate between the α and β phase about 523 K. A simple model for the oxide growth mechanism is given.