Board Thread:General Discussion/@comment-28135006-20170505061835/@comment-1600847-20170706095657

We can only speculate if ESO is cannon or not for now. While I personally believe it's all going to retconed by a Dragon Break, we'll have to wait until TES 6 comes out to know for sure. If we see a book or NPC in TES 6 detailing, for example, the events of the Alliance War or the Planemeld, we'll know it's cannon.

But unless Bethesda flat out states it's not cannon, we on this wiki assume, as with all games with "The Elder Scrolls" in the title, that it's cannon.