* TheCastShowoff: Yes, that really is Creator/RachelLuttrell singing in the episode "Critical Mass". They actually had to fly her to Los Angeles to re-record her singing in that episode because her first take sounded ''too'' good, that is, too much like a classically trained singer (which Rachel Luttrell is, but Teyla Emmagan is not). She's also an accomplished dancer, which allowed the producers to give Teyla a much more theatrical fighting style than most other characters.
* TheDanza: Chuck the Technician, played by Chuck Campbell. He got his name when Creator/TorriHigginson accidentally called him by his real name in a scene instead of his character's rank (Sergeant) and it was left in as AscendedFanon.
* {{Defictionalization}}: In "[[Recap/StargateAtlantisS01E16TheBrotherhood The Brotherhood]]", Rodney mentions that there's an active Mensa chapter on Atlantis (there's also one in the alternate Rodney's reality in "[[Recap/StargateAtlantisS03E08McKayAndMrsMiller McKay And Mrs. Miller]]"). The [[http://www.columbus.us.mensa.org/ Columbus, Ohio Area Mensa]] received temporary permission from Mensa to sell buttons saying "Atlantis Chapter" with profits going to scholarship funds.
* DevelopmentHell: Production for the direct-to-DVD film ''Extinction'' never really got off the ground and was effectively ended after the cancellation of ''Series/StargateUniverse''. There was apparently an attempt from Creator/JoeFlanigan himself to buy or lease the rights to ''Atlantis'' to continue making the show in Europe. It fell apart when the company that owned it was bought out by another company that decided to cancel sister show ''Series/StargateUniverse'' and ended anything planned for ''Atlantis''.
* DyeingForYourArt: Ultimately subverted. Creator/JasonMomoa decided to cut off his dreadlocks for the fifth and final season as his character was going to have an ImportantHaircut in "Broken Ties". After the scene was shot, Syfy felt the dreads should stay put, so the scene was cut and Momoa wore a wig for the entirety of the season as a result.
* FakeAmerican: Most of the main cast are Canadians playing Americans. In the original cast, only Joe Flanigan (American playing an American) and David Hewlett (Canadian playing a Canadian) were actually playing their correct nationalities. They are, by coincidence, also the only characters to appear in every episode of the series.
* FakeBrit: Fake Scotsman, specifically. While Paul [=McGillion=] himself is Canadian, he was born in Scotland to Scottish parents and lived there at various times during his childhood. His accent is affected however.
* FakeNationality: [[PlayingWithATrope Sort of]]. Many of the actors were born in the countries that their characters are from, but they emigrated to Canada at young ages. For example, David Nykl is Canadian, but Czech-born and a native speaker of Czech. He is fluent in Czech but normally speaks English with a Canadian accent. He fakes the Czech accent (with pretty much 100% accuracy) when playing Zelenka.
* TheOtherDarrin: Elizabeth Weir was played by Creator/JessicaSteen during her first appearance on ''Series/StargateSG1''. Torri Higginson took over the role in the ''SG-1'' Season 8 two-part premiere. [[spoiler:Higginson was then replaced by Michelle Morgan as a Replicator version after the Asurans destroyed her body.]]
* PropRecycling
** The show got most of the set from ''Film/BladeTrinity''. The most prominent example is a curved bridge that shows up several times, such as in the hurricane episode.
** The Genii pistols are nicknamed [[http://www.imfdb.org/wiki/Stargate:_Atlantis#Genii_pistol_-_Dressed_up_Taurus_PT99AF_aka_The_Timecop_Beretta "Timecop Beretta"]], since the props were first used in the ''Film/{{Timecop}}'' movie with Creator/JeanClaudeVanDamme.
* RealLifeRelative: David Hewlett's sister Creator/KateHewlett plays Rodney [=McKay's=] sister Jeannie Miller. In "Hot Zone", [=McKay=] was orginally supposed to mention he had a ''brother'', but David Hewlett asked if he could change the line to ''sister'', in the hopes that he could get his real-life sister to star alongside him.
* RealitySubtext:
** When Col. Samantha Carter leaves ''SG-1'' to [[{{Transplant}} become leader of the Atlantis Expedition]], she says, "I know I am going to miss this place, and all of you," to old friend Teal'c. The tears in Creator/AmandaTapping's eyes were likely not faked; she herself was saying goodbye to ''SG-1'' after ten years.
** Creator/JasonMomoa got a large tattoo on his left forearm between the filming of seasons two and three, forcing Ronon to likewise get a tattoo in the series. This was applied in "Reunion", where the application apparently hurt and forced Ronon to lightly slap the person doing the inking; Jason had not told the producers about the tattoo, and they were unhappy to learn about it after the fact.
** Teyla became pregnant in the fourth season when Rachel Luttrell became pregnant in real life.
** Amelia Banks, one of the [[MauveShirt recurring control room technicians]], is a proficient student of UsefulNotes/{{Kickboxing}}. Her actress, Sharon Taylor, is a kickboxer in real life, and when the producers learned this about her they wrote it into the character.
* RecycledScript: Many episodes reused plots from ''SG-1''. It is always {{lampshaded}}.
* ThrowItIn: After Torri Higginson accidentally called the Gate Technician by his real name, "Chuck", the producers decided to keep it in and make it has official name, since he had not had one until that point.
* YouLookFamiliar
** Craig Veroni, who played Dr. Peter Grodin, first appeared in ''Series/StargateSG1'' as an unnamed weapons officer aboard the ''Prometheus'' in the episode "Grace". It was never confirmed if the two were the same character, or if Craig had been re-cast as a different person.
** The Lord Protector from "The Tower" originally appeared twice in ''SG-1'' as Harlan, the amazingly annoying inhabitant of Altair who turned SG-1 into robots.
-->"Komtraya!"
** Creator/JewelStaite was a Wraith before she was Dr. Keller. Not very noticeable however, since the Wraith part required full prosthetic make-up that made her virtually unrecognizable.
** In a fairly ludicrous example, in the early episode [[Recap/StargateAtlantisS01E07PoisoningTheWell "Poisoning the Well"]] Allison Hossack ended up playing the ''exact same role'' to one she did in the ''Series/StargateSG1'' episode "Cure" where Tretonin is discovered.
** Creator/ChristopherHeyerdahl played a character named Pallan on ''SG-1'', and the Athosian Halling on ''Atlantis''. His largest role is the Wraith Todd. At one point he even portrayed both Halling and Todd ''in the same episode'' (without any shared screentime however). He also played another, unrelated Wraith on Michael's hive for a few episodes in season 3.
** Paul [=McGillion=], who plays Dr. Carson Beckett, first appeared in the Stargate 'verse as Young Ernest Littlefield in the ''SG-1'' episode "The Torment of Tantalus". Incidentally, he was the first human to travel through Earth's Stargate in modern times.
** Garwin Sanford played the Tollan Narrim in the ''SG-1'' episode "Enigma", and also plays Dr. Elizabeth Weir's fiancé Dr. Simon Wallis.
** Captain Alicia Vega, introduced in season five, had previously appeared in "The Tao of Rodney" as a scientist that Rodney overhears (telepathically) saying that Ronon is "hot". After Vega died, her actress joked that she still has a twin sister serving on the city that could appear in future episodes.
** Mike Dopud played a Runner named Kiryk in ''SGA'', but he also played a BountyHunter in ''SG-1'' and a Lucian Alliance member in ''SGU''. Amusingly enough, the bounty hunter and Lucian Alliance member worked for the same organization. There has been fanfiction that speculates they were the same character.
** Richard Kind (Lucius Lavin) played Dr. Gary Myers (the guy whose translation Daniel corrected) in ''Film/{{Stargate}}''.
** Megan Leitch played both Ke'ra ([[spoiler:a de-aged version of Linea, a biochemical terrorist/mad scientist]]) and Helia, the arrogant Lantean warship captain.
* WhatCouldHaveBeen: Has [[WhatCouldHaveBeen/StargateAtlantis its own page]].