Dota 2 is a multiplayer online battle arena video game and the stand-alone sequel to the Defense of the Ancients (DotA) mod. Developed by Valve Corporation, the game was officially released on July 9, 2013 as a free-to-play title for Microsoft Windows, concluding a beta testing phase that began in 2011. OS X and Linux versions of Dota 2 were released on July 18, 2013. In most regions, Dota 2 is exclusively available through Valve's content delivery platform, Steam.

Each match of Dota 2 is independent and involves two teams, both containing five players and each occupying a stronghold at either end of the map. Located in each stronghold is a building called the "Ancient"; to win, a team must destroy the enemy's Ancient. Each player controls a "Hero" character and focuses on leveling up, collecting gold, acquiring items and fighting against the other team to achieve victory.