Fallout Online is a cancelled MMO that was in development at Masthead Studios and to be published by Interplay. The game's development began sometime after Interplay sold the partial rights to the Fallout intellectual property to Bethesda Softworks and Zenimax Media in 2004. The terms of the deal would allow Interplay to keep the rights to the previously developed titles such as Fallout, Fallout 2, and Fallout Tactics: Brotherhood of Steel, while Bethesda gained the right to create new games in the franchise, beginning with Fallout 3. However, Interplay also retained the rights to create an MMORPG set in the Fallout universe.
On May 16th 2010, Interplay officially launched the Fallout Online website and began accepting applications for the beta. However, On January 1, 2012, it was announced that the game has been cancelled as part of a legal settlement between Zenimax and Interplay. Interplay will also relinquish the remaining rights to the Fallout brand in December of 2013.