Stargate (movie, multiple television series)

Stargate concerns travel through an ancient network of gateways that connect habitable planets. Stargate SG-1 was a ten years long television show. Stargate Atlantis was a television science-fiction series as well.
Eugene Ipavec, 17 October 2005, Corentin Chamboredon, 3 September 2014, and André Coutanche, 3 October 2005

The sci-fi series "Stargate SG-1" concerns travel all over the Milky Way galaxy, most of them ruled by a race of parasitic aliens, the Goa'uld, who have been snatching humans from Earth for ages for use both as host bodies and as slaves (to whom they represent themselves as gods). The series has featured quite a few vex-objects. Planetary flags are quite commonly employed, and several of the Goa'uld System Lords appear to have banners of some kind as well — one is visible at at Stargate Wiki.
Eugene Ipavec, 27 July 2005 & 17 October 2005

Cimmeria

At Stargate Wiki, it is said that the Hammer is the symbol for the planet Cimmeria, a world forbidden to the Goa'uld.
António Martins-Tuválkin, 17 October 2007

Earth

Stargate symbol

The address-symbol for Earth is a crossbar-less "A" thing. The symbol is the origin point of Earth, those origin symbols being unique to each stargate in the galaxy. It represents a pyramid with a stargate on its top.
Eugene Ipavec, 27 July 2005 and Corentin Chamboredon, 3 September 2014

Flag

In the early seasons of Stargate SG-1, only the US and Russian governments are aware of the Stargate network, but only the US has the resources necessary to explore it. This makes for some awkwardly universal instances of US nationalism: for example, one episode revolves around an attempt to negotiate a place for Earth within the protective sphere of influence of a friendly alien species. In the negotiations, the entire Earth is represented solely by the US, and so the only thing behind the human seat at the three-party talks is the Stars and Stripes. I suppose the series' writers might have had the fastidious Tollans try to diplomatically avoid such an implication by assigning the human delegation at their inquest a flag with a neutral symbol, simply the gate coordinate for "Earth."
Eugene Ipavec, 5 September 2014

The flag is vertical, with a blue field, and the symbol of the Tauri (Earth) planet in white. This flag is not used by the Earthlings but on Tollana, a human populated alien planet, to represent Earth during a trial. The symbol is the origin point of Earth.
Corentin Chamboredon, 3 & 5 September 2014

Later in the series, other major nations are brought on board, and a secret international body is formed to conduct "foreign" policy, though the US still dominates it. I don't think this body, the UN-like IOC, has any sort of symbol, so the Tollan one-off is probably the only time in the series Earth is represented collectively in a genuine way.
Eugene Ipavec, 5 September 2014

The symbol on the banner appeared in the original "Stargate" movie and represented the Earth: Wikipedia.
Tomislav Todorovic, 5 September 2014

This is sort of interesting in that the item in question is a (fictional) planetary flag intended to represent Earth, but one not chosen by anyone from Earth. Instead it is a kind of placeholder selected for humans by an external agency.

I don't know what the term for this would be exactly. "Imputed" and "ascribed" carry the wrong connotations. An assigned flag? Ordained? Imposed? Is there a definition for the (earthbound version of the) concept in the DoV?
Eugene Ipavec, 5 September 2014

Stargate Command

A version of the stargate command flag is seen in the first season of the series Stargate SG-1. It is similar to the one seen later on, but the flag is black and the logo in white.
Marc Pasquin, 1 January 2016

In a recent episode, a character gets teleported into the briefing room sans his clothing. He is forced to improvise a kilt — sarong? — out of the flag. In the process we get a good shot of the graphic — a rather garishly-colored version of the SGC logo on a white background. The logo is a stargate — the ring-shaped thing — superimposed with a dialing chevron — the "V"-shaped thing — superimposed in turn with the address-symbol for Earth: the crossbar-less "A" thing.
Eugene Ipavec, 27 July 2005

Non-fictional flags

In 'Stargate Atlantis', each of the characters in the multi-national team has his or her national flag on his or her shoulder. Lots of Stars & Stripes; one of the lead characters is Canadian, so we have a Maple Leaf; and in the first 'establishing' episode there were lots of people at the Stargate base with Russian, German etc. flags on their shoulders. But another of the main characters is the Scottish doctor, who wears not a Union Jack but a Scottish Saltire. The series is roughly 'present-day', though, not set in some future where there is an independent Scotland.
André Coutanche, 3 October 2005

Galar

On a recent episode of Stargate SG-1, Collateral Damage, a planetary flag made an appearance. The flag of a planet called Galar is a tricolor of red-white-light blue, with a black emblem in white stripe, resembling a spiked ball with a white X inside it. Looks rather Dutch.
Eugene Ipavec, 15 April 2006 & 2 April 2007

The flags (there are two of them visible in a setting that appears several times throughout the episode) are hanging from indoor poles, and they appear with the red on top. That is entirely consistent with the way vertical tricolours (such as the French one) show up in similar displays. The hoistmost stripe seems to be on top because it's the one that's attached to the pole.
Jorge Candeias, 1 April 2007

Incidentally, Wikipedia had an image of the Galar flag too; it was in agreement with Jorge's. They got the color of the spiked-ball wrong, though.
Eugene Ipavec, 2 April 2007 & 7 May 2007

Goa'uld

The Goa'uld are not a united front; the most powerful of them, who hold the title "System Lord," spend most of their time at war with one another, using their vast armies of human worshippers to contend for resources, territory or simply ego. There is a weak ruling body, a semi-formal conclave of System Lords, but the only Goa'uld flags in evidence in the series are those of the individual Lords. The banners of three of them — Cronos, Nirrti, and Yu — appear in the season 3 episode Fair Game, but not clearly enough to reproduce, though. They are vertical and bright-red, one bears a gilded representation of a snake-like Goa'uld symbiote.
Eugene Ipavec, 17 October 2005

Jaffa

In Stargate SG-1, in the season 9 episode Origin, Part 2, there is a formal summit between Earth and a leader of the Jaffa, once the human soldiers of the Goa'uld aliens, who had recently revolted and overthrown them. The leader is preceded by heralds with a banner — either his or that of the Jaffa collectivelly — which is vertical and hangs from an elaborate armature in the shape of an upside-down 'L' — exactly like the banners used earlier in the series by the Goa'uld System Lords. It is a lighter shade of blue, with some curvy gold calligraphy, probably thicker than I have it here, and a horizontal line near the bottom.
Eugene Ipavec, 17 October 2005

Langara

Kelowna Hierarchy

The flag of the Kelowna Hierarchy, a nation-state of the planet Langara, appears in a goverment bunker in an episode at the end of season 6. It is black, with a odd-looking irregular silver crescent — resembling the head of a wrench — in its center, and a downward-aimed golden dagger superimposed over it.
Eugene Ipavec, 17 October 2005

The Stargate races "Kelownans" and "Langarans" are named for real places in British Columbia (the show is filmed there). Apparently, the Kelownans in the show were written as 'bad guys' after the City of Kelowna was uncooperative to the show's film crews. Langara is probably best known as the name of a college in Vancouver, which includes courses in film and acting (so there are bound to be Langara grads working on the show).
Dean McGee, 2 September 2006

Ori

By the end of season 8 of Stargate SG-1, the Goa'uld have been badly weakened, and demoted to the level of a nuisance, clearing the way for a new set of heavies, the Ori, who are — in a novel touch — not fake gods, but the genuine article. Being the disembodied descendants of the ancient Stargate-builders, they are nearly omnipotent, demand worship from humans, and rule over billions of faithful. They inhabit an adjacent galaxy, from whence they dispatch missionaries to this one as a prelude to a crusade-type invasion force.
Eugene Ipavec, 17 October 2005

Origin

The flag of their religion, called Origin, can be seen hanging off the facade of the temple in the village of Ver Ager in the Stargate SG-1 season 9 episode Origin, Part 2. It is dark blue with a black border and black symbol of Origin, which recurs constantly in the Ori's domains.
Eugene Ipavec, 17 October 2005

Unidentified Ori flag or ensign

This is a different flag of the Ori from the sci-fi series Stargate SG-1. It appeared quite recently. I am not entirely sure of its exact connotation, however.

In the series' current plotline, the malevolent and godlike Ori have created a young woman whom they call "The Oreci" to serve as an intermediary between them and their human worshippers and lead their expeditionary forces in this galaxy.

In the episode Counterstrike", the flag was shown hanging on a low armature standing on a balcony next to the Oreci while she was giving a proselytic speech to the denizens of a newly converted planet.

This could make it the overall "national" symbol of the followers of the Ori, or a special flag of the crusade to convert the Milky Way; however, the two emblems of the Ori on it make it seem almost like a rank flag of some kind, leadind me to suspect it may have been meant to be the personal flag of the Oreci herself.
Eugene Ipavec, 31 August 2006