A grease composition for a constant velocity joint contains a base oil containing 2 to 25 wt. % of a thickener based on total weight of the composition, 0.5 to 20 wt. % of boron nitride powders based on total weight of the composition, and 0.1 to 10 wt. % of an extreme pressure agent based on total weight of the composition selected from the group consisting of molybdenum dithiocarbamate, a sulfur and phosphorus-containing extreme pressure agent, and mixtures thereof. The boron nitride powders have mean particle size of more than 5 .mu.m and not more tha 20 .mu.m.