Over the years, there have been 1366 Star Wars tagged questions on SFF:SE. These have attracted some great answers from a wide variety of sources including the Star Wars films, comics, games, TV shows, novels, art-books and RPGs. The number one response asked in comments is always “how canon is that source?“.

With the purchase of LucasFilm by Disney there have been some recent changes to the way in which Star Wars licensed properties are managed. I thought that now would be a good time to provide the definitive guide (I wish) to the New Star Wars Canon.

Canonicity in the Star Wars universe is, as of April 2014 determined by a working group comprised of representatives of Disney and LucasFilm known as the Lucasfilm Story Group.

The primary change made is that the old canon system (G-Canon, T-Canon, etc) has been nuked from orbit and only the original six feature films (the Original Trilogy and the Prequel trilogy), Clone Wars TV show, Clone Wars film and Star Wars : Rebels TV shows are considered to be part of the official Star Wars film canon.

All other properties (with a few small exceptions) are now lumped together under a single banner known as Star Wars : Legends. Those exceptions seem to include the film’s novelisations (where they elaborate on things seen on screen), the official StarWars.com Data Bank (which replaces the old Data Bank website) and elements of the Jedi Path Manual.

“While Lucasfilm always strived to keep the stories created for the EU consistent with our film and television content as well as internally consistent, Lucas always made it clear that he was not beholden to the EU. He set the films he created as the canon. This includes the six Star Wars episodes, and the many hours of content he developed and produced in Star Wars: The Clone Wars. These stories are the immovable objects of Star Wars history, the characters and events to which all other tales must align.”

LucasFilm Statement – Apr 2014

Those other film and TV properties that were originally deemed to be G-Canon and T-Canon (the Star Wars Radio Dramatisations, Star Wars Holiday Special, Ewoks films, Star Wars : DroidsTV show and Star Wars: Ewoks TV show) are now all considered to be Legends properties.

Moving forward, all future properties (films, books, comics and games) will be licensed and fully compliant with the Star Wars Story Group’s rules regarding canon status, unless explicitly stated. Excluding the exceptions listed above, the full list of canon works (past, present and near future) now stands as follows:

(Film) Episode I: The Phantom Menace (and the novelisation by Terry Brooks)

(and the novelisation by Terry Brooks) (Film) Episode II: Attack of the Clones (and the novelisation by R. A. Salvatore)

(Film) The Clone Wars (and the novelisation by Karen Traviss)

(TV Show) The Clone Wars: Season 1-5

(TV Show) The Clone Wars: The Lost Missions

(Comic) Darth Maul: Son of Dathomir by Jeremy Barlow

(Novel) Dark Disciple by Christie Golden (not yet released)

(Comic) Kanan: The Last Padawan by Greg Weisman (not yet released)

(Film) Episode III: Revenge of the Sith (and the novelisation by Matthew W. Stover)

(Novel) Lords of the Sith by Paul S. Kemp (not yet released)

(Novel) Tarkin by James Luceno

(Novel) A New Dawn by John Jackson Miller

(Novel) Servants of the Empire: Edge of the Galaxy by Jason C. Fry

(Novel) Ezra’s Gamble by Ryder Windham

(TV Show) Star Wars Rebels: Spark of Rebellion

(TV Show) Star Wars Rebels: Season 1

(Film) Episode IV: A New Hope (and the novelisation by Alan Dean Foster)

(Comic) Star Wars by Jason Aaron

(Comic) Star Wars: Darth Vader by Kieron Gillen (not yet released)

(Comic) Star Wars: Princess Leia by Mark Waid (not yet released)

(Short Story) One Thousand Levels Down Alexander Freed

(Novel) Heir to the Jedi by Kevin Hearne (not yet released)

(Film) Episode V: The Empire Strikes Back (and the novelisation by Donald F. Glut)

(Film) Episode VI: Return of the Jedi (and the novelisation by James Kahn)

(Short Story) Blade Squadron by David J. Williams

(Film) Episode VII: The Force Awakens (and the novelisation). (not yet released)

Original answer to the question How is canonicity of derivative works determined for Star Wars?