This article is concerned with the effects of the silane surface treatment of silicon dioxide (SiO₂) on the tribological properties of the SiO₂-reinforced polymethyl methacrylate (PMMA) (SiO₂/PMMA) composites filled with carbon fiber (CF). Silane treatment and CF bring positive effect to improve friction reduction and antiwear properties of SiO₂/PMMA composites. Fourier transform infrared analysis shows that SiO₂ has been oxidized and etched by silane treatment. The presence of active groups increases the polarity of SiO₂, and so the bonding property between the particle and the matrix improves. The scanning electron microscopy (SEM) observation revealed that this hybrid reinforcement could be interpreted in terms of a positive rolling effect of the particles between the two sliding surfaces, which protected the short CFs from being pulled out of the PMMA matrix.