The effect of an inorganic oxidation inhibitor, such as MoSi2, on the surface energetics of carbon-carbon composites has been studied. According to contact angle measurements based on a linear fit method obtained from multiple testing liquids, such as water, diiodomethane, ethylene glycol, and glycerol, it is observed that increasing the MoSi2 filler content of the composites leads to an increase of the surface free energy, mainly due to the increase of the London dispersive component of surface free energy, even if its specific or polar component is decreased. As an experimental result, the London dispersive component is strongly dependent on the results of the interlaminar shear strength of the composites, In this work, it has been possible to show that the results obtained from the linear fit method correlate with those determined from a two-liquid geometric mean when water and diiodomethane testing liquids are considered as a two-liquid pair.