La Blizzard Entertainment è una casa produttrice di videogiochi statunitense fondata l'8 Febbraio 1991 con il nome di Silicon & Synapse da tre laureati dell'UCLA, Michael Morhaime, Allen Adham and Frank Pearce, ed attualmente è una filiale della società americana Activision Blizzard. L'azienda con sede a Irvine, California, in un primo momento si concentrò nella conversione di giochi per conto di altre aziende, prima di iniziare lo sviluppo del proprio software nel 1993 con la pubblicazione di giochi come Rock' n Roll Racing e The Lost Vikings.Nel 1994 l'azienda cambia il proprio nome e diventa "Blizzard Entertainment Inc", prima di essere acquisita dal distributore Davidson & Associates e successivamente da Vivendi.Poco dopo, la Blizzard mette a segno il colpo della svolta: "Warcraft: Orcs & Humans". La Blizzard ha continuato a creare diversi video-giochi di successo, tra cui il sequel di Warcraft, StarCraft e la serie di Diablo e inoltre il gioco di ruolo online multigiocatore di massa (MMORPG) "World of Warcraft". I loro progetti più recenti includono la quarta espansione di World of Warcraft, Mists of Pandaria, la prima espansione di StarCraft II, Heart of the Swarm, e Diablo III.

Il 9 Luglio 2008 la Activision si fonde ufficialmente con la Vivendi Games, includendo anche il marchio Blizzard nella holding societaria risultante, anche se Blizzard Entertainment rimane un'entità separata con gestione indipendente. Blizzard Entertainment offre eventi per incontrare i giocatori e per annunciare giochi: BlizzCon in California, Stati Uniti e il Blizzard Worldwide Invitational in altri paesi, come ad esempio a Parigi, Francia e a Seoul, Corea del sud. All'inizio del 1994 sono stati acquisiti dal distributore Davidson & Associates per 6,75 milioni di dollari americani. Lo stesso anno la società assunse il nome Chaos Studios, prima di cambiarlo nuovamente in Blizzard Entertainment, dopo aver scoperto che esisteva già un'altra società con il nome Chaos. Poco dopo, Blizzard mise a segno il colpo della svolta: "Warcraft: Orcs & Humans".

Blizzard has changed hands several times since then: Davidson was acquired along with Sierra On-Line by a company called CUC International in 1996; CUC then merged with a hotel, real-estate, and car-rental franchiser called HFS Corporation to form Cendant in 1997. In 1998 it became apparent that CUC had engaged in accounting fraud for years before the merger; Cendant's stock lost 80% of its value over the next six months in the ensuing widely discussed accounting scandal. The company sold its consumer software operations, Sierra On-line which included Blizzard, to French publisher Havas in 1998, the same year Havas was purchased by Vivendi. Blizzard was part of the Vivendi Games group of Vivendi. In July 2008 Vivendi Games merged with Activision, using Blizzard's name in the resulting company, Activision Blizzard.

In 1996, Blizzard acquired Condor Games, which had been working on the game Diablo for Blizzard at the time. Condor was renamed Blizzard North, and has since developed hit games Diablo, Diablo II, and its expansion pack Diablo II: Lord of Destruction. Blizzard North was located in San Mateo, California; the company originated in Redwood City, California.

Blizzard launched their online gaming service Battle.net in January 1997 with the release of their action-RPG Diablo. In 2002, Blizzard was able to reacquire rights for three of its earlier Silicon & Synapse titles from Interplay Entertainment and re-release them under Game Boy Advance. In 2004, Blizzard opened European offices in the Paris suburb of Vélizy, Yvelines, France, responsible for the European in-game support of World of Warcraft. On November 23, 2004, Blizzard released World of Warcraft, its MMORPG offering. On May 16, 2005, Blizzard announced the acquisition of Swingin' Ape Studios, a video game developer which had been developing StarCraft: Ghost. The company was then merged into Blizzard's other teams after StarCraft: Ghost was 'postponed indefinitely'. On August 1, 2005, Blizzard announced the consolidation of Blizzard North into the headquarters at 131 Theory in UC Irvine's University Research Park in Irvine, California. In 2008, Blizzard moved their headquarters to 16215 Alton Parkway in Irvine, California.

World of Warcraft was the fourth released game set in the fantasy Warcraft universe, which was first introduced by Warcraft: Orcs & Humans in 1994. Blizzard announced World of Warcraft on September 2, 2001. The game was released on November 23, 2004, on the 10th anniversary of the Warcraft franchise.

The first expansion set of the game, The Burning Crusade, was released on January 16, 2007. The second expansion set, Wrath of the Lich King, was released on November 13, 2008. The third expansion set, Cataclysm entered into closed beta testing in late June 2010 and was released to the public on December 7, 2010.

With more than 10 million monthly subscriptions in October 2010, World of Warcraft is currently the world's most-subscribed MMORPG, and holds the Guinness World Record for the most popular MMORPG by subscribers. In April 2008, World of Warcraft was estimated to hold 62 percent of the MMORPG subscription market. In 2008, Blizzard was honored at the 59th Annual Technology & Engineering Emmy Awards for the creation of World of Warcraft. Mike Morhaime accepted the award.

As the website Gamasutra in February 2012 writes, Blizzard Entertainment will lay off around 600 employees "in order to address the changing needs of our company", as the Blizzard CEO and co-founder Mike Morhaime in a statement said. Blizzard has a location in Austin, Tx.