ZrB2–SiC–TaC ceramics with different content of TaC were prepared by hot-pressing at 1800°C in vacuum environment. The oxidation behavior of these ceramics was studied in the temperature range of 1200°C–1500°C in air. It was found that low concentration of TaC (10 vol%) deteriorated the oxidation resistance of ZrB2SiC, while high concentration of TaC (30 vol%) significantly improved the oxidation resistance of the ceramics. Reoxidation experiments indicated that the metallic species (tantalum and/or silicon) diffusing out of the materials into the oxides was initially involved in the controlling process.