* [[AuthorExistenceFailure Actor Existence Failure]]: When asked about sequels, Straczynski was known to say that he didn't see how it would be possible "so long as Andreas Katsulas, (G'Kar) and Richard Biggs (Dr. Franklin) remain dead." That said, he did ''The Lost Tales'' after their passing, and now with his Hollywood success, there seem to be very early feelers out about a real [[TheMovie movie]].
* AuthorPhobia: JMS has said that Londo's dream of standing on his homeworld and watching the sky slowly fill with the Shadow ships was based on one of his own recurring nightmares. He had been curious if other people would find it as terrifying as he did.
* CriticalResearchFailure: In the UK's captioning of the show anyway; When Garibaldi heralds an invasion by playing a recording of PorkyPig going "Th-th-th-that's all folks!" the captioning misattributes the quote to BugsBunny.
* DuelingShows: With ''Series/StarTrekDeepSpaceNine''.
** JMS had pitched ''Babylon 5'' to Paramount (who turned it down) a year before they announced the new ''Star Trek'' series [[ThereAreNoCoincidences "On a space station, near a portal allowing travel across the galaxy"]].
** ''B5'' made a little dig at ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'' in its second season:
--->'''Ivanova:''' "[[BreakingTheFourthWall This isn't some deep-space franchise]], this station is ''about'' something!"
*** The writer of that episode, of course, was PeterDavid, who was also a prolific writer for the ''Franchise/StarTrek'' ExpandedUniverse, and who wasn't afraid to take a good-natured dig at B5[[note]]Or at least, take a dig at JMS[[/note]] while writing for ''SpaceCases''.
**** David was surprised, however, when JMS said that he intended on keeping the line in there as is. His exact words were "You people really are dangerous over there."
** Lennier also manages to take a minor stab against Scotty, when Sheridan asks for [[TimTaylorTechnology more power to the engines]]: ''"If I were holding anything back, I would tell you."'' (When Scotty came back for an episode of TNG, he revealed that he would often hold back reserve power behind the captain's back, so he could turn the ship UpToEleven when Kirk inevitably asked for more.)
** In "Babylon Squared" Garibaldi insists upon accompanying Sinclair and company to the time distortion; Sinclair refuses, saying it is unwise to have the [[TheMainCharactersDoEverything entire command staff away from the station]] at such a critical moment, an obvious dig at the ''Franchise/StarTrek'' franchise's tendency to have the most or all of senior staff away from the ship on an away mission.
** Majel Barrett guest starred in the third season as Lady Morella, the third wife to the late Centauri Emperor, as a means to quell the fan-anger between the shows. She'd previously been one of the biggest ''Trek''-associated supporters of the show, frequently telling fans at conventions to check it out.
** Of course, the shows shared quite a few writers and guest actors between them, with one or two of the B5 cast appearing in guest roles on ''Series/StarTrekDeepSpaceNine'' after B5's conclusion.
** There are even similarities and parallels between the shows in theme and naming: the Roman Empire based Centauri and the Romulans, the deeply introspective and ascetic Minbari/Vulcans, the previously conquered and recently freed Narns / Bajorans & Klingons (the Narn are an interesting mix of Klingon warrior cult and Bajoran religious fanatics), the meddling and nearly omniscient Vorlons / Q, and the assimilating tyrannical inhuman Shadows / Borg. Of course, the most blatant parallel is the Minbari Leader Dukhat and the Cardassian leader Dukat.
*** That said, while both shows share many elements, the way they ''use'' those elements are quite different, and take both shows in very different directions. The best example of that being the Dukhat-Dukat naming parallel, where the two characters share next to nothing else in common.
* EnforcedMethodActing: In ''Severed Dreams'', we see an ISN Newscast get cut short when an explosion rocks the building. Debris can be seen landing on the newsdesk, with the anchors crying out in fear. The debris wasn't ''supposed'' to land that close to the actors, and their reaction to almost having it land on their heads was genuine.
* ExecutiveMeddling:
** The character of Warran Keffer existed purely because of this, the studio demanded a hot-shot crack pilot character. Naturally, he got killed off at the earliest possible opportunity. Actually he wasn't that bad a character all told, though some of his dialog was rather cheesy.
** The reason why the end of season 4 seems so crowded, and the beginning of Season 5 seems mostly composed of filler, is because the show was originally going to be cancelled after four seasons due to the failure of the Creator/{{PTEN}} network. The events of season 4 (originally intended to end with the episode "Intersections in Real Time") were shortened by four episodes, after which the resolution to the Earth Civil War arc (originally meant for the beginning of season 5) was resolved in three super-dense [[WhamEpisode Wham Episodes]] followed by the GrandFinale. Then at the last minute the show's fifth season was picked up by cable network TNT -- but now there was almost no material left for the fifth season's first half. A new season 4 finale was hastily shot, (the already-shot GrandFinale "Sleeping in Light" delayed to the series' end) and the eleven-episode hole was filled by the telepath-colony arc (originally meant to be just three episodes), the arc of Londo and G'Kar on Centauri Prime (originally cut from season 4), and standalone filler episodes ranging in quality from the yawner "A View from the Gallery" to NeilGaiman's marvelous "Day Of The Dead".
** In the Babylon 5 script books, {{Word of God}} states that he had Season Five plotted out... and then his [[NoPlansNoPrototypeNoBackup only copy of his notes were stolen while at a con]]. The resulting attempts to recover them led to the self-admitted awkwardness of Season Five... of course, this still wouldn't be necessary if it weren't for the potential canceling of the season. Executive & Obsessed Fan meddling?
* FakeRussian: American actress Claudia Christian portrays the supposedly born-and-raised Russian Susan Ivanova, but barely gives herself any accent beyond occasionally giving herself a stilted speech pattern in some early episodes.
* HeyItsThatGuy:
** Primary and recurring cast members included Andrea Thompson (''Series/{{JAG}}'', ''Series/NYPDBlue''), Bruce Boxleitner (''Film/{{Tron}}'', ''Series/ScarecrowAndMrsKing''), Bill Mumy (''Series/LostInSpace''), Stephen Furst (''Film/AnimalHouse''), Jeff Conaway (''Film/{{Grease}}'', ''Series/{{Taxi}}''), and Creator/WalterKoenig.
** Guest appearances included [=Bruce McGill=] (''Film/AnimalHouse''), [=David McCallum=] (''Series/TheManFromUNCLE'', ''Series/SapphireAndSteel''), Creator/DavidWarner, Creator/BradDourif (''Film/ChildsPlay''), Creator/JeffreyCombs, Ken Foree (''Film/DawnOfTheDead''), Russ Tamblyn (''TwinPeaks''), Creator/WilliamSanderson (''Film/BladeRunner''), Creator/DwightSchultz, Paul Winfield (''Film/StarTrekIITheWrathOfKhan''), Richard Moll (''Series/NightCourt''), Creator/HarlanEllison (as a Psi Cop), and June Lockhart (''Series/LostInSpace'', ''Series/{{Lassie}}''). Majel Barrett-Roddenberry (The whole ''Franchise/StarTrek'' franchise) did a guest appearance as a gesture to reconcile the ''Trek''/''B5'' FandomRivalry.
** While Londo was his most visible role, Peter Jurasik is a character actor with over thirty years and 70 roles under his belt; for our purposes it's most interesting that he, like Boxleitner and David Warner, was in ''Film/{{Tron}}'' (as CROM, an accounting program destined for the games grid).
* HeyItsThatVoice: Numerous examples.
** Byron the telepath is also the Medic from ''VideoGame/TeamFortress2'', among many others.
** When the computer is rebooted after a systems shutdown, it comes back online with an obnoxious, stubborn personality voiced by Creator/HarlanEllison.
** Ellison also provided the voice for Zooty's talking prop when comedians Rebo and Zooty visited the station.
** Ardwright Chamberlain -- Nicolai of ''ShadowHearts: Covenant'' -- is Kosh.
** Mel Winkler, Aku Aku from the ''Franchise/CrashBandicoot'' series, appears in the episode "And The Rock Cried Out, No Hiding Place".
** In the 2002 TV movie ''Legend Of The Rangers'', Sarah Cantrell is played by Myriam Sirois -- better known to a generation of North American anime fans as the voice of Akane Tendo from the English dub of ''[[RanmaOneHalf Ranma 1/2]]''.
** Kathryn Cressida who plays Kat the Bartender, seen in the first two seasons in the Earth Force bar, shouldn't be allowed near the fusion reactor's button or she might say, "[[Westernanimation/DextersLaboratory Oooh. What does this button do?]]"
* LineToGod: JMS was a frequent poster on the {{Usenet}} group rec.arts.tv.scifi.babylon5.moderated during the show's run.
* TheOtherDarrin:
** [[spoiler: Anna Sheridan (played by Beth Toussaint) first appeared in a message to her sister-in-law, recorded prior to her disappearance. Toussaint wasn't available for the episode where Anna returns as a Shadow agent; Melissa Gilbert (Bruce Boxleitner's real-life spouse) was cast in her place]].
** Delenn's mentor, Draal, is played by Louis Turenne in the two-parter "A Time in the Wilderness". In all of his subsequent appearance, he is played John Schuck. This is {{Hand Wave}}d by explaining that Draal has [[FountainOfYouth age-regressed]] as a result of being linked with the Great Machine.
** Apparently they had a terrible time keeping actresses around to play G'Kar's aide. His first one, Ko'Dath, disappears under mysterious circumstances because Mary Woronov had trouble with the Narn makeup and prosthetics. The same problem drove away the first Na'Toth actress, Susan Kellerman. Julie Caitlin Brown made it through the entire first season (and was awesome) before she, too, succumbed to makeup problems and quit. Her role was given to Mary Kay Adams, who was not up to the task at all, and finally Na'Toth was written out of the story altogether. (However, she is later mentioned as having been captured by the Centauri during the war, and [[spoiler: is found by Londo and G'Kar in a prison cell on Centauri Prime in Season 5. For this appearance, she is once again played by Julie Caitlin Brown]].
* PlayingAgainstType: Creator/WalterKoenig is best known for playing ButtMonkey Chekov in ''Series/StarTrekTheOriginalSeries''. Here he plays the ruthless MagnificentBastard Alfred Bester with intimidating charisma.
* PropRecycling: In "Babylon Squared", and again in "War Without End", space suits from ''TwoThousandTenTheYearWeMakeContact'' were used. They changed their appearance as much as they could, but some people still recognized them, and assumed it was meant as a ShoutOut.
* RetroactiveRecognition:
** Mira Furlan (Delenn) went on to play a [[WildHair wild-haired]] CrazySurvivalist on ''Series/{{Lost}}''.
** Ken Jenkins (Trevor Hall, captain of the Heracles) later played Dr. Kelso on ''Series/{{Scrubs}}''.
** Matthew Stoner [[Series/{{Angel}} only got creepier as he got older]]. Plus he ''really'' hates spiky-haired vampires.
** Creator/BryanCranston appears in "The Long Night" as a dedicated Ranger captain.
* ScienceMarchesOn: In ''Believers'' Doctor Franklin wants to perform a surgery to remove a blockage in the lung of a sick alien boy. His parents object to cutting him open because it's against their religion. Nowadays, this surgery could be done without any cutting at all[[note]]beyond hacking up the blockage to facilitate removal, that is[[/note]], by use of an [[http://en.wikipedia.org/wiki/Endoscope endoscope]].
** RuleOfDrama: [[CriticalResearchFailure Endoscopic surgery was commonplace in the 1990's when the show first aired]]. If anything, Franklin should have even ''more'' advanced techniques to work with, but the episode simply would not work as written otherwise (and it sets up a major plot point for two later episodes--both involving this same species, [[SchizoTech which managed to develop interstellar travel but neglected medicine]]).
* TechnologyMarchesOn: The thick digital tablets used by the station personnel might have looked futuristic in the mid 90's when the show was produced. Also, the [[SnowyScreenOfDeath snowy static]] shown on a screen whenever a camera is taken out is jarring if you are used to modern screens that simply switch to a blank black or blue screen when their signal is lost.
** Then there are the computer interfaces; the buttons look like colorful candy, and the interfaces look like a child's computer game...from the 80's.
** The operation that Franklin performs on the alien child in the first season can now be done non-invasively, requiring no cutting of the body. [[spoiler:This probably would have kept the kid's parents from helping him perform ritual suicide afterwards due to their belief that the soul leaves the body if it is cut open]].
* ThrowItIn: The Centauri hairstyle resulted from an attempted practical joke by Peter Jurrasik about his idea for their hair, which JMS went along with because he wanted the actors to feel like he valued their input, and by the time the situation became clear it was too late to go back. It did end up working pretty well by making the Centauri visibly different from humans.
** Averted for the most part. [=JMS=] was very much against ad-libbed lines, since he was careful about how every line was written in order to avoid screwing up the MythArc. In the few cases where it did happen, he had very serious talks with the actor involved (such as when Bill Mumy/Lennier hummed a mantra that turned out to be the title of the album his band made). One notable case where an addition was allowed is in ''The Fall of Night'', the Season 2 finale. The Earth Ambassador tells Ivanova that his pen was a gift from his wife. After mentioning this, he kisses the pen. [=JMS=] states in that episode's commentary that when he asked the actor why he did that, the actor responded "Well, my wife isn't here, so I can't kiss her, so I kiss the pen instead." [=JMS=] then chuckles and says "Ah, actors. Someday they'll all be replaced with CG. I'm kidding. No I'm not. Yes I am."
** One very notable ad-lib that got kept: in the broken elevator scene of the episode "Convictions", G'kar was originally supposed to sound grim and unyielding. G'kar's actor, Andreas Katsulas, instead chose to speak the words almost maniacally. After the take, [=JMS=] realized that the acting resulted in a [[CrowningMomentOfFunny one of the funniest moments of the show]].
* TropeNamer:
** AllLoveIsUnrequited: "Rising Star", courtesy of Ivanova (of course).
** DeathOfPersonality: A form of capital punishment practiced by Earth Alliance, actual execution having been outlawed except in mutiny and treason cases. Also known as mindwipe, and first spoken of in "The Quality of Mercy".
** NothingIsTheSameAnymore: "Chrysalis", in the final line of that Season.
** TravelingAtTheSpeedOfPlot
** TouchedByVorlons: "The Wheel of Fire"
* TrueCompanions: Most of the B5 core cast is still tight-knit to this day, particularly Claudia Christian, Bruce Boxleitner, and Mira Furlan. (Furlan even says that Boxleitner is still their "Captain.") Andreas Katulas and Peter Kurasik were best friends up until Katulas' death from terminal lung cancer. The only two who don't get along are Claudia Christan and JMS himself; they're still sniping at each other through tell-all books and interviews.
* WhatCouldHaveBeen: The role of Knight Two in "And the Sky Full of Stars" was originally offered to [[ThePrisoner Patrick McGoohan]] (who couldn't fit it into his filming schedule) and then WalterKoenig (who was too ill to take it). Koenig, of course, was [[HappyEnding later cast as Alfred Bester]].
** Commander Takashima would have been revealed to be housing a Psi-Corps sleeper personality if Tamlyn Tomita had stayed, and it would have been her who shot Garibaldi at the end of season one.
* WordOfGay: Well, Word Of Bi. For both Lochley (according to Neil Gaiman) and Cartagia (according to Wertham Krimmer). Although in both cases there was definite innuendo on-screen.
** JMS once asked actor Wortham Krimmer to tone down Emperor Cartagia's fey behavior, to which Krimmer responded, "Well, Joe, he's bisexual, don't you know." When JMS gave an "oh really" sort of reply, Krimmer said, "Absolutely. He's the emperor. He can f--- anyone he wants."
* WordOfGod: JMS remained active on USENET throughout the show's run, and would often answer questions about the B5 'verse posted to rec.arts.sci-fi.tv.babylon5.moderated.
----
* HugoAward: The Hugo award the show won, for either "''The Coming of Shadows''" (1996) or "''Severed Dreams''" (1997) appeared in on Ivanova's desk in "''Sleeping in Light''"

* Back when nearly all of the World Wide Web could be linked to on one page, it seemed that most web sites had some sort of sci-fi series tribute somewhere. ''Series/StarTrekTheNextGeneration'' was a particularly popular choice for enshrinement (it was on at the time, see?). B5 has one up on it, though: the NCSA Mosaic ''browser'' had a semi-secret page (about:b5) where the developers expressed their love for the series and provided a few links to fan sites in case you wanted to learn more.