We discuss the Raman scattering of thermally oxidized gallium selenide (GaSe) and indium selenide (InSe) single crystals. It has been established that the oxidation mechanisms of these compounds are rather different. For InSe, an increase of the oxidation temperature leads to the formation of (SeO₄) complexes. For GaSe, it is characteristic that only Ga₂O₃ is formed as an oxygen-containing phase during the oxidation. The presence of the Me₂Se₃ phase (where Me is Ga or In) in its own oxide is common for both of the semiconductors.