NTN Corporation (NTN株式会社, NTN Kabushiki-gaisha) (a.k.a. Niwa, Tomoe, Nishizono) is one of the most prominent manufacturers of bearings in Japan, second domestically only to NSK Ltd. The company is one of the largest exporters worldwide of friction-reducing products, such as constant-velocity joints.

It is listed on the Tokyo Stock Exchange and is a component of the Nikkei 225 stock index.

It was competitor Nippon Seiko (now known as NSK) which began the Japanese bearing industry in 1914 by producing such bearings. Four years later in 1918, Nishizono Ironworks, a factory in Uchibori, Mie Prefecture, began producing ball bearings.

Five years after Nishizono Ironworks began its production of these friction reducing components, the company merged with Tomoe Trading to fabricate and market them under the name "NTN". In 1927, however, Nishizono and Tomoe split, with the former company setting up a new company called "NTN Manufacturing Company".

In 1934, the company reorganized as a joint-stock company, changing its name to Toyo Bearing Manufacturing. When Japan invaded Manchuria, the demand for bearings increased due to the war, and manufacturing productivity followed suit. In 1938, Toyo created a domestic subsidiary named Showa Bearing Manufacturing Company, in Mukogun, Hyogo Prefecture. Toyo absorbed Showa into its organization the following year, making the facility into its Mukogawa plant and merging Mukogawa's operations with those of their newly established plant in Kuwana.

By 1945, raw materials shortages that resulted from World War II rendered Japanese bearing manufacturers unable to produce at full capacity. However, in the late 1940s, as Japan recovered from combat, demand from the war-torn country and its intracontinental neighbors increased.

At the end of the decade, Toyo created a marketing division called NTN Sales, at the same time, becoming one of the five most prominent bearing manufacturers in Japan, alongside Koyo Seiko, Nippon Seiko, Asahi Seiko and Fujikoshi Kozai. They, along with the other four aforementioned companies held over 75% of that country's bearing market the following year. Three years later, in 1954, NTN Sales received the Deming Prize for statistical quality control while continuing to diversify its product offering. In 1956, the company started to manufacture expansion compensating bearings.

Due to the incredible growth that Toyo underwent, the organization decentralized by creating subsidiaries to oversee new products. In 1961, Toyo set up a joint venture with INA Wälzlager Schaeffler called NTN Wälzlager Europa in order to manufacture needle bearings. Toyo utilized design data from INA Wälzlager Schaeffler to make these products. They also established Kongo Bearing Company to manage the creation of pillow block bearings. One year later, Toyo founded Senyo Kosakuki Kenkyujo, a maker of ball bearing equipment. In 1963, Toyo entered into business with Hardy Spicer to produce Birfield-type constant-velocity universal joints. They also pursued business overseas by establishing NTN Bearing Corporation of America. The following year, working with GKN Transmission, the company fabricated constant-velocity joints in their home country and formed NTN Bearing-GKN while also opening a facility in Europe called NTN France. The year after that, Toyo started manufacturing oil-impregnated sintered bearings and pipe fittings. Four years later in 1968, the company set up yet another facility in North America called NTN Bearing Corporation of Canada.