The effects of Ga and Sn additions, with an almost constant value regarding Al equivalence, on the creep properties and oxidation resistance of the near-a Ti alloy Ti-5Al-4Zr-1Mo were investigated. The creep strain rate increased due to the replacement of Sn with Ga, which was accompanied by an increase in the volume fraction of primary equiaxed a phase. In addition, the replacement of Sn with Ga decreased the activation energy of the steady-state creep rate for the similar volume fraction of the equiaxed a phase. Ga addition improved the oxidation resistance without Ga segregation at the TiO 2 /substrate interface, whereas Sn promoted oxide spallation with metallic Sn segregation at the interface. Ga uniformly dissolved into the internal TiO 2 and into the external Al 2 O 3 as a result of solid solution formation between Ga 2 O 3 and the aforementioned oxides, which suppressed oxide growth. The formation of (GaAl) 2 TiO 5 in TiO 2 and Al 2 O 3 was also discussed on the basis of the phase relationships in the TiO 2 -Al 2 O 3 -Ga 2 O 3 system.