Kinetics of air oxidation of MgO–C–Al refractory at 600°–1300°C were investigated using the software based on the modified shrinking core model (KDA). Commercial bricks containing 88.5% MgO, 10% residual carbon, and 1.5% aluminum anti-oxidant were oxidized isothermally with air. Combination of experimental data with model calculations indicated gas diffusion through solid material and pores as a major controlling step. Previously observed chemisorption process was eliminated from the rate-controlling mechanism with addition of aluminum antioxidant. Comprehensive rate equations were devised for MgO–C–Al and MgO–C oxidation reactions. Overall activation energies of Qid (internal diffusion)=139.15 kJ/mol at T≤800°C and Qpd (pore diffusion)=25.48 kJ/mol at T>800°C were obtained for MgO–C–Al oxidation reactions. Corresponding values were determined to be Qid=134.85 kJ/mol and Qca (chemical adsorption)=66.69 kJ/mol at T≤800°C and Qpd=18.95 kJ/mol and Qca=66.69 kJ/mol at T>800°C for MgO–C oxidation reactions. Addition of aluminum anti-oxidant indicated a reducing effect on oxidation of MgO–C bricks at 800°C≤T≤1250°C. Reverse behavior was observed at T≤700°C.