The present paper discusses the effects of friction stir processing (FSP) on properties of Mg–SiC nanocomposite. The magnesium-based RZ5 alloy, widely used for aerospace applications, was used in the present investigation as the matrix for the purpose of nanocomposite fabrication. SiC powders of nanosize were reinforced into the RZ5 matrix by FSP with varying process parameters. The process was studied with respect to the effects of parameters such as rotational speed, traverse rate, and number of passes on the nanocomposite. With appropriate parameters, uniform distribution of nanoSiC reinforcements was accomplished in the metal matrix. The abrasive wear property of the Mg–SiC nanocomposite was verified with respect to the FSP process parameters. A mathematical model was also developed to predict the strength and abrasive wear characteristics of the nanocomposite with respect to the FSP parameters. © 2017, The Brazilian Society of Mechanical Sciences and Engineering.