
Square Enix Holdings Co., Ltd. is a Japanese entertainment conglomerate and video game company best known for its Final Fantasy, Dragon Quest and Kingdom Hearts role-playing video game franchises, among numerous others. Outside of video game publishing and development, it is also in the business of merchandise, arcade/amusement facilities and manga publication under its Gangan Comics brand.
Dozens of Square Enix companion books have been produced since 1998, when video game developer Square began to produce books that focused on artwork, developer interviews, and background information on the fictional worlds and characters in its games rather than on gameplay details. The first series of these books was the Perfect Works series, written and published by Square subsidiary DigiCube. They produced three books between 1998 and 1999 before the line was stopped in favor of the Ultimania series, a portmanteau of ultimate and mania. This series of books is written by Studio BentStuff, which had previously written game guides for Square for Final Fantasy VII. They were published by DigiCube until the company was dissolved in 2003. Square merged with video game publisher Enix on April 1, 2003 to form Square Enix, which resumed publication of the companion books.

Beautiful Game Studios is a British video game developer based in London, England. The studio was set up in 2003 to take over the development of the Championship Manager after its former developer Sports Interactive ceased its involvement. Beautiful Game Studios was majorly restructured in November 2009, losing 80% of its staff.

Core Design Limited was a British video game developer based in Derby. Founded in May 1988 by former Gremlin Graphics employees, it originally bore the name Megabrite until rebranding as Core Design in October the same year. The company was acquired by umbrella company CentreGold in December 1994, which in turn was acquired by Eidos Interactive in April 1996. In May 2006, the Core Design personnel and assets were acquired by Rebellion Developments, and the company became Rebellion Derby, which was then shut down in March 2010.

Eidos-Montréal is a Canadian video game developer based in Montreal. The studio is owned by Square Enix Europe, a subsidiary of Square Enix.

Ion Storm, L.P. was an American video game developer founded by video game industry veterans John Romero and Tom Hall, both formerly of id Software. Despite an impressive pedigree and high expectations, the company only produced one commercial and critical success, 2000's Deus Ex.

Kingdom Hearts is a series of action role-playing games developed and published by Square Enix. It is a collaboration between Square Enix and The Walt Disney Company and is under the direction of Tetsuya Nomura, a longtime Square Enix employee.

Last Order: Final Fantasy VII , also abbreviated as Last Order or LO, is a 2005 Japanese anime original video animation produced by Madhouse and released by Square Enix. It was directed by Morio Asaka, and produced by Masao Maruyama, Jungo Maruta and Akio Ofuji. Tetsuya Nomura served as supervising director. The OVA is an alternate rendition of two flashbacks used for the video game Final Fantasy VII. Last Order was released in Japan with Advent Pieces: Limited, a special edition release of the film Final Fantasy VII: Advent Children, and as a bonus feature in the North American "Limited Edition Collector's Set" release.

SCi Entertainment Group plc was a British video game publisher based in London. The company was founded in 1988 by Jane Cavanagh and floated on the stock exchange in 1996. In May 2005, SCi acquired Eidos, the parent company of publisher Eidos Interactive, and merged their operations by June 2006. In December 2008, SCi was briefly renamed Eidos and was subsequently taken over by Square Enix in March 2009.

Silicon Dreams Studio Limited was a British video game developer based in Adderbury, England.

Square Enix Collective is an indie initiative and self-titled "service provider for Indie developers", which helps get a developer's game published while maintaining their creative control. It is a division of Square Enix Europe, created by Phil Elliot in 2014, with a focus on generating indie awareness.

Square Enix Montreal is a Montreal-based studio under video game developer Square Enix best known for creating the Go series of turn-based puzzle games for smartphones and tablets based on former Eidos Interactive intellectual properties. Founded in November 2011 as a traditional studio with plans to create a new Hitman series game for consoles and employ several hundred people, its mandate changed in 2013 when it became its parent company's choice studio to produce mobile games, beginning with the Hitman franchise. The company developed prototypes for two mobile Hitman games, which became the board game-inspired puzzle game Hitman Go (2014) and the shooter Hitman: Sniper (2015). The commercial success of the latter and the critical success of the former led to two additional titles in the Go series: Lara Croft Go (2015), based on the Tomb Raider series, and Deus Ex Go (2016), based on the Deus Ex series. The studio legally belongs to Square Enix Europe and is operated separately from Eidos-Montréal studio, another Montreal-based studio owned by Square Enix Europe.

Symphonic Odysseys: Tribute to Nobuo Uematsu was a symphonic tribute concert held in Cologne, Germany on July 9, 2011 at the Cologne Philharmonic Hall. The concert exclusively paid homage to the work of Japanese composer Nobuo Uematsu and featured music selected from his works as a video game music composer. Among the games featured were Lost Odyssey, Blue Dragon, Last Story, King's Knight, Chrono Trigger, Final Fantasy Legend, and selected works from the Final Fantasy series. The concert was produced and directed by Thomas Böcker, with arrangements provided by Finnish composer and musician Jonne Valtonen, along with Roger Wanamo, Masashi Hamauzu, and Jani Laaksonen. The concert was performed by the WDR Rundfunkorchester Köln and the WDR Radio Choir Cologne under conduction from Arnie Roth, with guest performers Benyamin Nuss and Juraj Čižmarovič joining the orchestra. A video recording of Symphonic Odysseys was streamed live online.

Taito Corporation is a Japanese company that specializes in video games, toys, arcade cabinets and game centers, based in Shinjuku, Tokyo. The company was founded by Michael Kogan in 1953 as the Taito Trading Company, importing vodka, vending machines and jukeboxes into Japan. It began production of video games in 1973. In 2005, Taito was purchased by Square Enix, becoming a wholly owned subsidiary by 2006.

Tokyo RPG Factory Co., Ltd. is a Japanese video game developer and subsidiary of Square Enix, a company known for its work in the role-playing genre. The company was founded in 2014 under the name "Tokyo Dream Factory" by Yosuke Matsuda, who became president of Square Enix in 2013. As of 2019, it has released three titles to varying degrees of critical and commercial success; I Am Setsuna, Lost Sphear and Oninaki. The three were each themed after the Japanese phrase Setsugekka. A fourth project is in the planning phase as of 2019.