An investigation of in-flight nitridation and carburization of MoSi2 powders has been carried out using the induction plasma process. Response surface methodology (RSM) with the Box-Behnken experimental design was utilized in this investigation, in order to study the influence of some induction plasma processing parameters on the efficiency of nitridation and carburization reactions performed on inflight treated MoSi2 powders. The parameters examined included the level of inductive power, reactor pressure, and the quantity of reaction gases supplied. Under the optimal process conditions achieved during this investigation, about 2.8 wt.% of nitrogen (in the case of nitridation) and about 8.0 wt.% of carbon (in the case of carburization) were able to be incorporated into the MoSi2 powder particles.