- Ghostbusters -All information from the movie. Some delete scenes are used as canon too, including the extra scene where Janine is wishing Egon best of luck on fighting Gozer.
- The Real Ghostbusters -While it is not entirely canon the name "Slimer" was first used in the cartoon series, also in the recent Ghostbusters: The Video Game, Slimer is sort of their pet as Egon is testing on him and keeping him in a tank on the first floor. The episodes Citizen Ghost and Partners in Slime also hint that The Real Ghostbusters may be canon with the movies after all. "Take Two" explained in a way, the differences between the cartoon and the film. The film according to the episode was made based on events in the cartoon. Inside jokes about the film are all over the episode. Louis Tully on one occasion has introduced himself as a "Tax Attorney". One of the few references to "Ghostbusters II" in the cartoon.
- Ghostbusters II -All information from the movie. Fans sometimes favor avoiding Louis Tully's relationship with Janine as it breaks the relationship between Egon and Janine built up in the first movie and The Real Ghostbusters.
- Ghostbusters Role-Playing Game -The scale and guide to the book series is used many times as canon in explaining the role of a ghostbuster and also what a ghost is.
- Extreme Ghostbusters -Not usually considered canon because there are hardly any references to the movies(though variations on various famous lines are spoken in some episodes).
- Ghostbusters: The Video Game -As of now Dan Aykroyd said that the game is canon, and was loosely based on a older script that was rejected that was going to be Ghostbusters III. However, so far it appears that the view is that Dan meant the "realistic versions" and not the "stylized versions" as they differ.
Reasons for Canon
During the late eighties The Real Ghostbusters series had in many ways led the franchise. The release of Ghostbusters II caused a clash in stories and development as the movie claimed the Ghostbusters had gone out of business due to the lack of spiritual activity. The lack of colored uniforms that had became a trademark thanks to the cartoon series were also gone. However, Slimer is an ally of the Ghostbusters, Winston is clean-shaven, and Janine has red hair and wears her glasses more often, just like in The Real Ghostbusters.
As of recently, the movie canon has seen some new development thanks to Ghostbusters: The Video Game which by Dan Aykroyd is canon and was declared to basically be Ghostbusters III. However, thanks to the popular response to the video game, the movie series may get a third installment after all.
Most information here came from "Ectozone's Omnibus Timeline" which was compiled by Fritz Baugh and was a effort of a lot of the ghosthead community.