World of Warcraft (WoW) is a massively multiplayer online role-playing game (MMORPG) released in 2004 by Blizzard Entertainment. It is the fourth released game set in the Warcraft fantasy universe. World of Warcraft takes place within the Warcraft world of Azeroth, approximately four years after the events at the conclusion of Blizzard's previous Warcraft release, Warcraft III: The Frozen Throne. The game was announced in 2001, and was released for the 10th anniversary of the Warcraft franchise on November 23, 2004. Since launch, World of Warcraft has had eight major expansion packs produced for it: The Burning Crusade, Wrath of the Lich King, Cataclysm, Mists of Pandaria, Warlords of Draenor, Legion, Battle for Azeroth and Shadowlands.

World of Warcraft was the world's most popular MMORPG by player count of nearly 10 million in 2009. The game had a total of over a hundred million registered accounts by 2014. By 2017, the game had grossed over $9.23 billion in revenue, making it one of the highest-grossing video game franchises of all time. At BlizzCon 2017, a vanilla version of the game titled World of Warcraft Classic was announced, which planned to provide a way to experience the base game before any of its expansions launched. It was released in August 2019.