A facile method was developed to prepare MWCNT/POSS nanocomposites by direct esterification between carboxylic acid functionalized MWCNT and octa(phenol) octasilsesquioxane. Completeness of the MWCNT surface modification was confirmed by FT-IR. The hybrid nano-MWCNT–OP-POSS composite structure and properties was characterized using DSC, TGA, optical microscopy, WAXD, and AFM. The results indicated the solubility and processability of MWCNT–COOH improved because of OP-POSS grafting on MWCNT surface. The T g and thermal stability of the nanocomposites was higher than that of the OP-POSS as a result of the cross-linking reaction. AFM observations revealed that the nanocomponents were reacted in a homogeneous phase at nanoscale level.