The oxidation kinetics of TiAl intermetallic at 500–900 °C in air is studied using a gravimetric method, and the phase composition of the scale is studied using an x-ray phase analysis. At t > 600 °C, the kinetics of oxidation is described by a parabolic equation. The oxides TiO2 (rutile), γ-Al2O3, α-Al2O3, Ti2O3 are found in the scale. It is shown that at the first stage the γ-Al2O3 and low-titanium oxides form on the sample surface at t < 70 °C. At t ≥ 850 °C, the Ti2O3 forms on the external surface of the scale, TiAl3 is found in the sublayer at the alloy/scale interface. It is shown that at t ≤ 800 °C the process is controlled by oxygen diffusion. At t > 800 °C, the oxidation mechanism changes: counterdiffusion of titanium ions through interstitial sites in TiO2 lattice occurs.