<p>This study examined the effect of synergistic alloying of near β-Ti(Al) with niobium (Nb) and tantalum (Ta) on oxidation resistance. Isothermal TGA tests at 1200&#xa0;°C showed that the (Nb + Ta)-containing alloy exhibited the lowest weight gain and slowest parabolic oxidation rate compared to alloys containing only Nb or only Ta. Isothermal oxidation tests in air at 1000–1200&#xa0;°C for 9&#xa0;h revealed that both Nb- and (Nb + Ta)-containing near β-Ti(Al) alloys formed an external oxide zone (EOZ) with rutile (TiO₂) and alumina (α-Al₂O₃) in the outward region, along with sporadic traces of Ta₂O₅ and Nb₂O₅ mixed with (Nb/Ta)-rich TiO₂ in the inward region. Fine lamellae of α-Al₂O₃ within Ti₃Al phase were observed in the internal oxide zone (IOZ). The observed trend in oxidation resistance was attributed to the increased oxygen ion vacancy formation energy in TiO₂ due to the addition of Nb and Ta. Additionally, the higher valence states of Nb and Ta than Ti contributed to reducing the fraction of oxygen vacancies, thereby suppressing the formation of TiO₂.</p> Graphical abstract <p></p>