NGK Spark Plug Co., Ltd. is the world's leading manufacturer of spark plugs, glow plugs, oxygen sensors (under the brand name NTK), and other components for internal combustion engines. The company produces components of industrial ceramics for semiconductors, communications equipment, etc. The headquarters of NGK Spark Plug Co., Ltd. are in Nagoya, Japan.

NGK now has plants and sales organizations in all parts of the world. 5 plants are located in Japan with 15 others worldwide. NGK employs around 10 thousand people. NGK is constantly working to develop new technologies, annually spending 11% of its turnover in research and development. NGK European Technical Centre in Ratingen (Germany), opened in 1990, with a total area of ??2200 square meters, provides all European car manufacturers support, which is necessary to check engine and chassis, cold climate simulation and specialized works on the analysis of exhaust gases.

NGK collaborates with leading car manufacturers, supplying components to assembly lines. Among these customers are Audi, Alfa Romeo, Bentley, BMW, DaimlerChrylser, Ferrari, Fiat, Ford, Honda, Jaguar, Lancia, Mazda, Mitsubishi, Opel, Renault, Skoda, Toyota, Volkswagen, Volvo, etc. According to NGK, more than 87% of the world's producers of passenger vehicles choose NGK spark plugs for the first set. As for European manufacturers, more than 50% of manufacturers including BMW Group, Fiat Group and VW Group fit NGK spark plugs.