Abstract: Sepiolite-fiber-reinforced polyoxymethylene (POM) composites were prepared, and the effect of fiber surface modification with a silane coupling agent, KH550, on the mechanical and tribological properties of the composites were investigated. The mechanical and tribological properties of the composites were improved with an increase of sepiolite fiber content. When 5.0 wt% of sepiolite fiber was added, the composites gained optimum mechanical and tribological properties and achieved the tensile strength of 68.43 MPa, the flexural strength of 89.81 MPa, the flexural modulus of 3600.61 MPa and the impact strength of 285.5 kJ/m2, which increased by 28.6 %, 51.9 %, 79.1 % and 8.8 %, respectively, compared to pure POM. However, the composites presented a friction coefficient of 0.072 and a wear loss of 3.6 mg, which decreased by 65.9 % and 35.7 %, respectively.