Frictional characteristics of glass fiber reinforced polymer (GFRP) composites are of technological interests for reducing wear in circumstances where they are applied. Graphene oxide (GO) is one 2D nanomaterial with an excellent lubricating effect. However, no work has been reported yet on the effects of GO coating on the frictional characteristics of GFRP composites. In this work, GO was grafted on GFs by a surface treatment method via silane coupling agent. Uncoated and coated unidirectional GF reinforced epoxy composites were prepared using a hot press process. The frictional characteristics of GF reinforced composites were investigated in two directions parallel and perpendicular to fiber direction by the pin-on-disk method under the pressure of 5–30 N at the disk rotating speed of 50–200 rpm. The results showed that the frictional stability was greatly improved by grafting GO on GFs. The friction coefficient of GO-coated glass fiber reinforced polymer (GO-coated GFRP) composite was generally lower than that of the GFRP composite under a low pressure of 5 N and showed the lowest average friction coefficient of about 0.10 at the rotating speed of 100 rpm in the direction parallel to the fiber alignment. For the raw glass fiber reinforced composite, the friction coefficient is high under low pressures at low rotation speeds while this tendency is inverse for the GO-coated GFRP composite. In addition, the anisotropy of the friction characteristics is not obvious under low pressures but becomes obvious at high pressures for both GFRP and GO-coated GFRP composites. Display omitted