A cover for use with a firearm sound suppressor comprises an insulating body and a retention apparatus attached to the insulating body. The insulating body includes one or more layers of thermally-insulating material. The insulating body is configured for being wrapped around the firearm sound suppressor. The retention apparatus includes a securing structure configured for being wrapped around the insulating body to secure the insulating body in a fixed position with respect to the firearm sound suppressor after the insulating body is wrapped around the firearm sound suppressor.