Microstructural evolution of Ti2AlN ceramics during high-temperature oxidation in air has been revealed by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEGSEM), and energy-dispersive spectroscopy (EDS). After oxidation below 1200 °C, layered microstructures formed on Ti2AlN surfaces containing anatase, rutile, and α-Al2O3. Above 1200 °C, more complex layered microstructures formed containing Al2TiO5, rutile, α-Al2O3, and continuous void layers. With increasing temperature, anatase gradually transformed to rutile, and TiO2 reacted with α-Al2O3 to form Al2TiO5. Based on these microstructural observations, an oxidation mechanism for Ti2AlN ceramics is proposed.