Sega Sammy Holdings Inc. (also known as the Sega Sammy Group) is a Japanese global holding company formed from the merger of Sega and Sammy Corporation in 2004. Both companies are involved in the amusement industry (Sega with arcade and home video games, Sammy with pachinko machines).

Sega was founded on June 3, 1960, by American businessman Martin Bromley.

The company started to distribute slot machines to U.S. bases in Japan. During the 1960s, Service Games was renamed to Sega Enterprises Ltd. Sega Enterprises sold their first product, the electro-mechanical game called Periscope which became a worldwide hit. In 1969, Sega Enterprises was acquired by U.S. conglomerate Gulf and Western Industries (which also owned famed movie studio Paramount Pictures around this time). In 1983, Sega launched the Sega Computer Videogame SG-1000, the first 8-bit video game platform. In 1986, the CSK Group acquired Sega Enterprises through capital participation. Sega Europe Ltd. was established in Europe, and in 1985, Sega Enterprises Inc. was established in the United States. These regional subsidiaries served as a marketing base for amusement arcade machines.

Sammy Corporation was founded on November 1, 1975, as Sammy Industry

Co., Ltd. by Japanese business magnate, Hajime Satomi. It was formed from Satomi Corporation's manufacturing and marketing divisions for amusement arcade machines. In the 1980s, Sammy marketed and sold Pachislot machines, and in the 1990s, Sammy expanded their portfolio by marketing and selling Pachinko machines. These two business ventures have been the primary pillar of Sammy Corporations revenue. During 1997, Sammy Industry Co., Ltd. changed its name to Sammy Corporation. By 2000, Sammy Corporation was listed in the Tokyo Stock Exchange's 1st section, indicating it as a "large company". Outside of Pachinko and Pachislot industry, Sammy Corporation was also involved in the video game industry as a publisher for fighting games such as the Guilty Gear series (developed by Arc System Works), The Rumble Fish series (developed by Dimps) and Survival Arts.

According to the first Sega Sammy Annual Report, the merger of the two

companies happened due to the companies facing difficulties. According to chairman Hajime Satomi, Sega had been in the red for nearly 10 years and lacked a clear financial base. Sammy, on the other hand, feared stagnation and overreliance of its highly profitable pachislot and pachinko machine business, and wanted to diversify its business in new fields, using Sega's broader range of involvement in different entertainment fields.

Together, as the Sega Sammy Group, the company has grown and acquired and founded multiple companies. Until 2015, the group was structured in four areas:

• The "Consumer Business", which contained video games, toys and animation.

• The "Amusement Machine Business" which contained Sega's arcade business.

• The "Amusement Center Business" which contained Sega's amusement centers and theme parks.

• The "Pachislot and Pachinko Business" is the Sammy Corporation and is the main pillar of the group's revenue.

On December 22, 2010, Sega Sammy Holdings acquired the remaining

outstanding shares of TMS Entertainment, thus making TMS Entertainment a wholly owned subsidiary of Sega Sammy Holdings. In April 2017, Marza Animation Planet, Sega's CGI animation studio, was restructured into TMS Entertainment.​

Sega Sammy Holdings announced in April that they have made a €706 million ($776 million USD) offer to acquire Rovio Entertainment. Rovio rejected an earlier acquisition bid from Israeli mobile company Playtika for $800 million. The deal closed on 17 August 2023, making the latter company a wholly owned subsidiary of Sega.