Thieves' Guild

""...the [Thieves'] Guild was given an annual quota which represented a socially acceptable level of thefts, muggings and assassinations, and in return saw to it in very definite and final ways that unofficial crime was not only rapidly stamped out but knifed, garroted, dismembered and left around the city in an assortment of paper bags as well.""

- Terry Pratchett, Equal Rites

Nobody can just be a criminal in this town. If you want to rob, extort, embezzle, pilfer, plunder or otherwise take what isn't yours, you need to be a member in good standing of the thieves' guild. Common to fantasy stories, the guild provides protection to its members (and eliminates their competition) in exchange for a cut of their ill-gotten gains. Sometimes, the guild will extend to assassins and other criminals; others handle only larceny. Similar to The Mafia, but there is no competing group of outlaws, nor solo operators. If you so much as cut a purse and you're not paying dues to the guild, someone cuts your throat.

Usually there is a boss of the thieves, who gets a cut of the proceeds from any heist. Most guilds have layers of organization; depending on how many, the people doing the actual thieving may get a minority of what they actually steal (there is more than one way to take someone's money). Often, thieving is treated as a craft, and would-be members must go through an apprenticeship before becoming true guild members.

Often, the legitimate powers that be will turn a blind eye to the guild's dealings, as long as the members lay off certain targets (e.g. nobles). Sometimes, the thieves' guild is more powerful than the recognized authority. There could easily be a civil war if the balance of power shifts or the authorities want something, however. If more than one guild begins to operate in town, the fantasy equivalent of a Mob War can easily break out.

While this is commonly regarded as a pure fantasy trope, there is actual historical precedent for it. Actual thieves' guilds with the trope characteristics existed in several cities of late-medieval France. The Yakuza families of Japan have in the past had a similar semi-tolerated status in Japan; some maintain they still do.

A type of Weird Trade Union, though a thieves' guild is usually more important to a story than most examples of that trope. Compare with Murder, Inc., The Fagin, The Artful Dodger, and Street Urchin.

If the authors don't think about it, may lead to a case of More Criminals Than Targets.

Comic Books

 * The Thieves' Guild and Assassins' Guild in X-Men
 * The Rogues from The Flash pay dues, have health plans and even consider themselves a branch of Keystone Local 242.
 * This was extended to The Syndicate and its involvement in the Las Vegas gambling scene during Peter David's run on The Incredible Hulk. At one point, the Hulk gets a job as a bouncer for Michael Berengetti, a wiseguy who blends his illegal dealings with his legitimate casino operations. When rival wiseguy Tony Gold wants to set up shop in Vegas, Berengetti orders him out of town, alluding to the "understanding" he and the other local casino bosses have with the authorities. So long as Berengetti and the other bosses only act within certain unwritten boundaries, the authorities leave them alone. In turn, Berengetti and the other bosses also get to take steps to "protect" their local market from outside competitors like Gold.

Film

 * In M, a Criminal Union (mostly made up of thieves, like the leader Safecracker) ally themselves with the local Beggars Union to catch a child-killer. This is mostly because the resulting police crackdowns are bad for business, but they also claim that even they won't tolerate a man who kills children. (A case of Truth in Television, as Fritz Lang noticed that a local criminals' union offered to help the police catch one of the serial killers he based the film on.)

Literature

 * The Jhereg Organization of Dragaera contains almost all organized crime in the Dragaeran Empire, including assassinations, illegal goods, untaxed gambling and lending, and thievery and selling stolen goods.
 * Older Than Steam: Miguel De Cervantes, of Don Quixote fame, wrote the short story Rinconete And Cortadillo, which has the two eponymous characters joining one of these.
 * Fagin's gang of pickpockets in Oliver Twist.
 * A thieves' guild figures big in David Eddings' Elenium and Tamuli—actually, each major city seems to have its own head-of-the-underworld, and each of the bosses know and keep in contact with the other bosses, and they meet every so often at the central city of the continent. The organization is loose, but they exchange favors and services for each other; one aspect is 'thieves' sanctuary'--a thief can go to another territory and ask to be kept safe. The local boss is entitled to refuse, but has to answer to the thief's own boss at the next meeting of the council. An unsatisfactory answer may result in a cut throat.
 * The Mockers in The Riftwar Cycle.
 * P.C. Hodgell's Chronicles of the Kencyrath features as the setting of the first book, "God Stalk", a city and Thieves' Guild based quite admittedly on Lankhmar.
 * Diana Wynne Jones' Dark Lord of Derkholm, which is set in a world that's been forced to adopt all the Fantasyland cliches for the benefit of the tourists, obviously has a Thieves' Guild. Interestingly, though, it turns out to be an authentic institution that's been around since before the whole tourism thing started.
 * Fritz Leiber's Fafhrd and The Gray Mouser stories have a Thieves Guild in the city of Lankhmar. This is certainly the Trope Namer and probably the Trope Maker, although borderline examples occur earlier.
 * Elizabeth Moon's The Deed of Paksenarrion has a thieves' guild; the guild, and one particular member of it, play significant roles in the climactic plot sequence.
 * There's a Caste of Thieves in the city-state of Port Kar on Gor.
 * Some of Andre Norton's Science Fiction novels had a Thieves' Guild IN SPACE!:
 * Forerunner Foray: the protagonist, Ziantha, was a member of the Guild who had Psychic Powers.
 * The Zero Stone: the protagonist, Murdoc Jern, was the adopted son of an appraiser who had retired from the Guild.
 * The Guild of Thieves, Cutpurses and Allied Trades and the Ankh-Morpork Thieves' Guild in Discworld is a sophisticated example. Lord Vetinari legalized them as one of his first acts upon becoming Patrician, reasoning that a police force would have to work harder to reduce theft, while the thieves' guild would have to work less. The system works fairly well - a customer can be robbed in the safety and comfort of their own home at the start of the year and afterwards walk the streets without fear (or with less fear than usual, this being Ankh-Morpork). The Guild has little tolerance of unlicensed theft, and won't cause too much trouble to the city now that they've become respectable and Vetinari knows where they live, who their wives are, and where their kids go to school. The head of the Guild is even one of the most important members of the city council (including important nobles and guild leaders), and in Feet of Clay someone even speculates that the head of the Thieves Guild might be interested in being the next Patrician with the implication this is actually possible. In fact, when the Watch is in need of extra manpower he shows up to help.
 * In The Lies of Locke Lamora, it's never called the Thieves' Guild, but virtually all of the thieves, cutpurses, burglars, con men, and related sorts were "the Right People." They gave the Capa a cut of their profits, and in return were part of his "Secret Peace": as long as they didn't steal from the nobles, they were relatively safe from the Duke's police forces.
 * Tortall has a thieves' guild (the Court of the Rogue) in more than one major city.
 * The Circle of Magic universe has organized street gangs, like the one that raised Briar. Mostly they steal and get in wars with each other.
 * In The Night Angel Trilogy, the Sa'Kagé is a particularly strong version of this.
 * In Dragonlance, the city of Palanthas has a Thieves' Guild, though this is noted to be unusual. The Palanthians actually take a sort of perverse pride in it, as they feel their guild thieves are higher class than thieves in other cities that don't have guilds.
 * The Forty Thieves of the Arabian Nights story Ali Baba and the Forty Thieves.
 * It's called the Brotherhood, the dominant part of the generally criminal "Outside," in M. K. Wren's The Phoenix Legacy trilogy. The appendices in the third book include a glossary of terms specific to Outsiders; for instance, "Tooky" is a form of address meaning, basically, "sucker."

Tabletop Games

 * Dungeons & Dragons:
 * In AD&D specific settings took over issues that belongs to them, so The Complete Thief's Handbook provided generic guide: outlined relationship with political, social and economical factors and expounded the variants of structure and internal policy for such guilds.
 * Later editions tend to stay away from a pure "Thieves' Guild" instead to have full-blown criminal organizations who who dabble in more crimes and for whom fencing is only one facet of their business.
 * Arguably the most famous Dungeons & Dragons thieves' guild are the Shadow Thieves of Amn, from the Forgotten Realms. Though as mentioned above, later editions have had the shadow thieves expand their business to a whole variety of crimes including smuggling and assassinations.
 * An interesting variation occurs in a couple of game settings, including the Dungeons & Dragons city of Greyhawk in the World of Greyhawk and Port Blacksand, the City of Thieves from the Fighting Fantasy Gamebooks series. In both cases, the Thieves' Guilds are actively involved in the government of the cities they operate in and contribute to its daily life. While both guilds have their own internal feuds and divisions, certain social conventions exist that keep the Guilds' internal struggles from harming the city at large. In Greyhawk's case, a high-ranking member of the Guild is the Lord Mayor.
 * Two rival Thieves Guilds, one staffed by cutthroat thieves, the other by vampires, play a prominent role in Baldur's Gate 2.
 * Magic: The Gathering gives us the Cateran mercenaries' guild in Mercadia.

Theatre

 * The play Sheik Rattle And Roll has the Forty Thieves of the Arabian Nights being unionised. In a scene set in a harem, they discover that the harem girls and eunuchs are also unionised, leading to an exchange of cards for the Amalgamated Thieves and Rogues Union, the Amalgamated Harem Girls and Dockers, and Amalgamated Eunuchs and Bacon Slicers (at which point every male character on stage crosses their legs. It's that kind of play).

Video Games

 * The Elder Scrolls:
 * In Arena they were a non-joinable faction that provided opposition for some randomly generated quests.
 * In Daggerfall you could join them.
 * Morrowind has two — the Imperial Thieves Guild and the non-joinable, xenophobic Cammona Tong — and in fact, one of the main points of the Thieves Guild quests is its war against the Cammona Tong. Note that here, the Cammona Tong is equivalent to the mafia, whereas the Thieves Guild behaves more like Robin Hood.
 * Oblivion has one. Official government policy is to deny its existence. Of course, this is probably a ploy of the Guild, considering the number of public officials who take bribes to look the other way.
 * Skyrim has one. Unfortunately, they're not as Robin Hood-esque as in the last game. Giving out threats, demanding payments and even having people falsely imprisoned. Thankfully they still have the standard of not killing people, but it's mostly because it's bad for business. They're close to death with influence only in Riften by the time of the game but the player can participate in jobs that can help spread their influence to the other holds, allowing them to bribe guards.
 * The Quest for Glory series has one in most games; usually, only thieves can find it.
 * Thief has one. Ironically, they are the title thief's enemies.
 * The collection information in Disgaea DS indicates that the Netherworld has one.
 * The Blackguards in Vacant Sky are a form of this trope. Of course, they take this to a new level, incorporating piracy, pillaging, and necromancy.
 * In Medieval II: Total War, spies and assassins are hired from taverns and inns but you can enhance their training by building a Thieves' Guild, which becomes available if you repeatedly hire assassins and spies from that settlement. Interestingly, the game notes that these Guilds are actually built and sanctioned by your government to train agents in not only bypassing but also improving security. As a result, any town with a Thieves' Guild in it becomes notably harder to infiltrate with assassins or spies.
 * These also exist in the Ultima series, and are often necessary to obtain certain critical supplies. The tinker class also seems to function as something of a stand-in for most games' Rogue class.
 * The Department of Shadowy Arts and Crafts, from Kingdom of Loathing.
 * The rogues in Diablo aren't just members of a thieves' guild, they're apparently members of a thieves' religious monastic order. They're also not thieves...
 * In Assassin's Creed II, Ezio has to team up with the Thieves' Guild of Venice. Turns out,
 * Baldur's Gate has one both in BG and SoA, in BG there is even a shoutout to Fritz Leiber as the code word to let  inside is "Fafhrd". in SoA it is the infamous Shadow Thieves.
 * In World of Warcraft, the city of Stormwind has SI:7, which is kinda like a rogue's guild, but pays its dues to the city and its rulers by acting as its spies and assassins.
 * In Tales of Vesperia there's made mention of the Dark Wings being the Thieves Guild of Terca Lumireis.
 * Guilds for thieves, assassins, and rogues all exist in Ragnarok Online for job-changing purposes, though you don't really see the NPC's working together in large numbers. Hilariously, said members are alarmed when being conversed with Knight/Crusader or Priest/Monk player character.
 * In Gothic II, Thieves' Guild is an Oddly Small Organization that dwells in an Absurdly Spacious Sewer. Lares serves as a One Man Thieves' Guild in Gothic III. Kinda.
 * Seiken Densetsu 3 has the Navarre Thieves' Guild.

Web Comics
"Sarine: Hm ... the same people who train the law enforcement also train the criminals ... what a remarkably efficient system. Ellis: When you say these things, do you even have trouble sometimes telling whether you're being sarcastic or not?"
 * Haley of Order of the Stick used to be a member of one.
 * The Thieves' Guild in A Modest Destiny, also double as something of an assassins' guild, employ Ninjas, and according to bonus material, were invented to balance out the economy.
 * In Snow By Night, Jassart and Blaise have formed their own little rook guild that has wards, people who pay the rooks so they can keep from getting robbed. One of the reasons the two are going after the Phantom Thief is because the culprit has stolen from their ward, Claudine, as well as the wards of other guilds.
 * Lampshaded and subverted in Errant Story, where the mercenary guilds in Farrel can work on either side of the law, according to the principle of supply and demand, as Jon explains. This give Sarine a marvelous opportunity to play Deadpan Snarker, which, of course, she puts to good use, only to have Ellis volley it right back to her.

Web Original

 * Neopets has had one since the early days of the site. Its most prominent appearance was in the Hannah and the Ice Caves plot, where they were the antagonistic side.

Western Animation
"Thief: A mere 50 denari. My card. If you are short we can arrange a payment plan. Good day!"
 * The Aladdin TV series often features a Thieves' Guild working in Agrabah. One episode had Jasmine trying to steal something to prove herself that she could be a "street rat" like Aladdin. She gets caught by a thief... who then hands her his card and tells her she has 30 days to obtain a Guild permit.

Real Life

 * In Real Life, gangs and organized crime in general fall under this category. In some cases, it's "As long as the people from the wrong side of the tracks don't come over HERE, we leave them alone", and in others, it's "As long as you keep bribing us, we'll let you go," ranging from unspoken to all-but-signed-contract level formality. The Yakuza even have a formalized understanding with the government in some areas of crime.
 * Jonathan Wild at one point secretly controlled almost all criminal activity in London, while publicly being hailed as its leading policeman.