NGK Insulators, Ltd. (日本碍子株式会社, nippon gaishi kabushikigaisha) (TYO: 5333) is a Japanese ceramics company. It primarily produces insulators but also produces other products, especially ceramic products. NGK is headquartered in Tokyo (Marunouchi Bldg. 25F, 2-4-1, Marunouchi, Chiyoda-ku, Tokyo 100-6325) and is listed on the Nikkei 225, which is an index of the Tokyo Stock Exchange.