Abstract: Ta–Al–N coatings were prepared using reactive magnetron cosputtering on silicon substrates. The coatings with a high Ta content exhibited a face-centered-cubic structure, whereas the coating with a high Al content exhibited a near-amorphous phase. To determine the oxidation resistance of the Ta–Al–N coatings, annealing treatments were conducted in air at 600–800 °C. Adding Al into a TaN structure increased the oxidation resistance to endure 8-h annealing at 600 °C. Moreover, the Ta35Al15N50 coating exhibited a superior oxidation resistance at 700 °C for 4 h. The material characteristics of the annealed Ta–Al–N coatings were examined through Auger electron spectroscopy and transmission electron microscopy and by using a nanoindentation tester.