The Elder Scrolls Online, abbreviated ESO, is a massively multiplayer online role-playing game (MMORPG) developed by ZeniMax Online Studios and published by Bethesda Softworks. It was released for Microsoft Windows and OS X in April 2014. It is a part of the Elder Scrolls series.
The game is set in the continent of Tamriel and features a storyline indirectly connected with the other games in the Elder Scrolls franchise. It had been in development for seven years before its release in 2014. It initially received mixed reviews, but these improved significantly with the re-release and rebranding as The Elder Scrolls Online: Tamriel Unlimited, with critics praising the changes that were made.
The Elder Scrolls Online originally used a mandatory monthly subscription model until it transitioned in March 2015 to a buy-to-play model with microtransactions and an optional subscription. The game was renamed The Elder Scrolls Online: Tamriel Unlimited and was released for the PlayStation 4 and Xbox One consoles in June 2015, and for PlayStation 5 and Xbox Series X/S in June 2021. The game sold more than 15 million copies by 2020, having around 2.5 million monthly active players in 2017.