TiAl-Mn-(0,5,10) wt.%Y2O3 alloys were prepared by the MA-SPS process, and their oxidation behavior was studied between 800 and 1000oC in 1 atm of air. The added Y2O3 particles were segregated along the matrix grain boundaries. The addition of (5~10) wt.%Y2O3, viz. (0.9~1.8) mol%Y2O3 increased the tendency to form the rutile phase along the grain boundaries, resulting in the increment of the oxidation rate and decrement of scale adherence. Mn was oxidized to Mn2O3. The primary mode of scale growth was the outward diffusion of Ti and Mn cations for the outer TiO2 scale, and the inward transport of oxygen anions for the inner (TiO2+Al2O3) mixed scale.