Self passivating tungsten-based alloys may provide a major safety advantage in comparison with pure tungsten (W) which is presently the main candidate material for the plasma-facing protection of future fusion power reactors. Films of binary and ternary tungsten alloys were synthesized by magnetron sputtering. The oxidation behaviour was measured with a thermo balance set-up under synthetic air at temperatures up to 1273 K. Binary alloys of W–Si showed good self passivation properties by forming an SiO2 film at the surface. Using ternary alloys the oxidation behaviour could be further improved. A compound of W–Si–Cr showed a reduction of the oxidation rate by a factor of 104 at 1273 K.