The effect of Mn alloying on the growth rate and oxidation resistance of MoSi2 coatings formed by pack siliconizing process, (Mo-Mn)Si₂ coatings formed by single-step pack process (codeposition of Si and Mn), and two-step pack process (manganizing+siliconizing), respectively, was investigated at 1373K and 1573K. The growth rate of MoSi₂ coatings was fast in order of two-step pack process, single-step pack process and pack siliconizing process at 1373K because the increase of Mn concentration on MoSi₂ coating surface resulted in the increase of mass balance condition of silicon for MoSi₂ growth. The static and cyclic oxidation resistance decreased in order of two-step pack process, single-step pack process, and pack siliconizing process in air at 1573K because higher levels of Mn tended to retard the growth rate of Mo_5Si₃ diffusion layer and rapid oxidation at the edge of MoSi₂ coatings was prevented by the formation of thick Mn-Si-O complex oxides and decrease of the formation frequency of microcracks within MoSi₂ coatings.