A study has been made of the effect of Li implantation on wear properties of glassy carbon (GC). Abrasive wear tests with a silicon carbide abrasive paper showed that Li implantation greatly reduced the wear volume of GC. Raman spectroscopy indicated that Li implantation changes the surface structure from disordered graphite to amorphous. Depth profiles of Li measured by secondary ion mass spectroscopy showed the migration of Li atoms towards the surface. It is concluded that the reduction of wear volume due to Li implantation may be caused by the formation of amorphous structure and/or the surface enrichment of implanted Li atoms.