Kingdom Hearts Timeline

Timeline: Lines where 2 titles appear together indicates that they run together. From earliest to latest.

Kingdom Hearts Birth By Sleep
A Fragmentary Passage
Blank Points (Part 1)
Kingdom Hearts
Kingdom Hearts/Kingdom Hearts 358/2 Days
Kingdom Hearts Chain of Memories/Kingdom Hearts 358/2 Days
Kingdom Hearts 358/2 Days*
Kingdom Hearts II*
Kingdom Hearts Coded
Kingdom Hearts II ending
Blank Points (Part 2)
Signs of What's Next
Kingdom Hearts 3D: Dream Drop Distance
Kingdom Hearts III

*: There could possibly be one more game, because there's one more unexplained story of the series mentioned by Nomura (Which were Xehanort's Past, Roxas' time with the Organization, King Mickey's Letter, and Riku's Absence) The first three were explained through Birth By Sleep, 358/2 Days, and Coded, respectively, but Riku's absence remains unexplained. Fans speculate that this is Riku's absence during KHII, but I believe it could be during Days. Anyway, the star denotes the timeline areas that this possible title could run alongside.

Other than the above note, the timeline is pretty much complete-- Nomura has said that:
~Kingdom Hearts III will be the end of the "Xehanort saga" which is pretty much collectively the series we know. Any games after this would be concerning something else (except for the above note.)
~Kingdom Hearts 3D: Dream Drop Distance will lead directly into KH3.
~Kingdom Hearts 3D: Dream Drop Distance follows Sora and Riku's Mark of Mastery exam, mentioned in Signs of What's Next.