Series of polyoxymethylene (POM) composites filled with three kinds of micro-sized reinforcing fillers, i.e. short carbon fibers (SCF), aramid particles (AP) and short glass fibers (SGF), with addition of polytetrafluoroethylene (PTFE) and/or silica nanoparticles were prepared. The tribological properties and transfer film structures were comprehensively investigated. It was revealed that mechanical properties of the micro-sized reinforcing fillers influenced significantly the tribological mechanisms of PTFE and silica nanoparticles in POM hybrid composites in aspect of transfer film formation. In comparison to SCF and SGF, AP played a better synergetic role with PTFE and SiO₂ nanoparticles in enhancing the tribological performance. It is assumed that tribo-physical and -chemical actions occurring on the reinforcements’ asperities are important for tribological behaviors of the composites.