Fallout canon is a set of ideas considered to be an official part of the Fallout universe.
Because each game of the Fallout series was created by a different development team and the plot and dialogues were created by mostly different people each time around, there are numerous inconsistencies between them and the canonicity of each game is a point of contention between various Fallout fans. For example, in case of inconsistency between games, some fans might consider newer entries in the series to override the older ones, while others might consider the original lore to still be "true" and inconsistencies to be mistakes on the part of the later titles' developers. Even various developers of one game might disagree on what holds true in the games' setting: for example, Tim Cain and Chris Taylor have different views on the origins of ghouls.
- Fallout and Fallout 2 are canon according to Bethesda, as Fallout 3 incorporates the majority of the back story of Fallout and Fallout 2.
- Fallout 3 and its DLCs are produced by Bethesda, therefore is canon, as are all other games and supplementary materials released by Bethesda.
- Fallout: New Vegas, which was published by Bethesda, is canon, as are all officially released supplementary materials, like the All Roads comic.
- Fallout 4 is being produced by Bethesda, therefore is canon.
As these works are established canon, events confirmed to have occurred in a later game can be referenced freely.
- Dogmeat is referenced in Vault Dweller's memoirs, which mentions that he died in the Mariposa Military base. This is canon and can be referenced freely.
- The EPA was cut from Fallout 2, and is not canon. Inclusion of this information should carry a cut content/non canon warning.
- Tycho is not referenced in future games. Whether or not he was recruited by the Vault Dweller is not established in Canon. It is okay to discuss Tycho in relevant contexts (Fallout NPCs, Junktown Quests, etc) and it is okay to include facts that are "history" at the start of Fallout (i.e.- that he was a ranger, that he was in Junktown, etc), but it is not okay to mention any possible fact that may depend on game outcome - e.g. we cannot put on the Vault Dweller page "The Vault Dweller recruited Tycho in Junktown".
- Fallout Tactics is considered semi-canon: major events are canon (and are referenced in Fallout 3), but some details are not. As part of the Fallout Tactics release, Fallout: Warfare has the same level of canonicity.
- Official Fallout Game Guides can be tricky to place. On one hand the developers of the games are involved during their production, through this the authors do have access to inside information that may not make it into a game. On the other hand, these guides have to be completed well in advance of release date, meaning some information can be changed between when the book went to print, and the eventual release. Information in these items can be considered canon (but should be referenced to the book with <ref> tags) unless directly contradicted in game. Where the books are contradicted, it is usually notable enough to make an appearance in the "Notes" section.
- Fallout: Brotherhood of Steel has been declared as non-canon by Bethesda Softworks, and Interplay prior to Bethesda's purchase of the franchise. Fallout: Brotherhood of Steel content should always contain a non canon warning.
- Fallout Shelter, while produced by Bethesda, is not canon as it has no narrative and focuses solely on gameplay and cameos.
- While Van Buren (the canceled Fallout 3 by Black Isle Studios) is not officially canon, some elements of it were incorporated into Fallout 3 and its add-ons, as well as into Fallout: New Vegas, and are now part of the Fallout canon. However in many cases people, places and concepts that were to appear in this game are very different to the portrayal in game. Van Buren content should include a non-canon warning unless verified from a canon source.
- The Fallout Bible by Chris Avellone is not canon, but serves as a useful commentary on the first two games. Some setting elements introduced in the Bible have been further developed in Fallout 3 and Fallout: New Vegas. Some erroneous elements of the Bible were later corrected either in following issues of the Bible, in the games or by the developers themselves. In 2011 Chris Avellone recommended against using the Bible to determine canonicity. Any content using the Bible without separate verification from a canon source should include a non canon warning.
- Similarly, cut content from Fallout 1 and 2 is non canon, but is a useful commentary on the games. Some cut Fallout 2 concepts have reappeared in different forms (such as the EPA's Hologram 00000 becoming Dr. 0).
- Canceled games that were not developed by Black Isle Studios, such as Fallout Extreme, Fallout Tactics 2, Fallout: Brotherhood of Steel 2, and Project V13 are non-canon and should always contain a non-canon warning.
The order of precedence, when listing Fallout games, should be canon games first, non-canon released games second, all other non-canon canceled games and ancillary works third, listed in order of first known development dates:
- Canon games
- Released non-canon games
- Canceled games and ancillary works
- Fallout Extreme - 2000
- Fallout Tactics 2 - 2001
- Fallout Bible - 2002
- Van Buren - 2003
- Fallout: Brotherhood of Steel 2 - 2004
- Project V13 - 2008