Six Flags, officially Six Flags Entertainment Corporation, is an amusement park corporation based in the United States, with properties in the US, Canada, and Mexico. It is the largest amusement park company in the world, based on the number of properties owned, and is ranked sixth in terms of attendance. The company maintains twenty properties throughout North America including theme parks, thrill parks, water parks, and family entertainment centers. In 2016, Six Flags properties hosted over 30.1 million guests.

Six Flags was founded in Texas and derived its name from its first property, Six Flags Over Texas. The company maintains a corporate office in Midtown Manhattan and its headquarters are in Grand Prairie, Texas. On June 13, 2009, the corporation filed for Chapter 11 bankruptcy protection, which it successfully exited after restructuring on May 3, 2010.

The name "Six Flags" refers to the flags of the six different nations that have governed Texas: Spain, France, Mexico, the Republic of Texas, the United States, and the Confederate States of America. The original park was (and still is) split into separate regions, such as the Spain and Mexico section which featured Spanish-themed rides, attractions, and buildings.

The Six Flags chain originated in 1957 with the creation of The Great Southwest Corporation by Angus G. Wynne and other investors. Construction of "Six Flags Over Texas" started in 1960, and the park was opened the next year for a short (45-day) season. The first park initially featured a Native American village, a gondola ride, a railroad, some Wild West shows, a stagecoach ride, and "Skull Island", a pirate-themed adventure attraction. There was also an excursion, inspired by the historical La Salle Expeditions in the late 1600s, called "LaSalle's River Adventure", aboard French riverboats through a wilderness full of animated puppets. Over time, all of those attractions, except for the railroad, would be replaced by others, such as roller coasters, swing rides, log flumes, and shoot-the-chute rides, as well as an observation tower.

The original park, in Arlington (between Dallas and Fort Worth) was sold in 1966 to a subsidiary of the Pennsylvania Railroad, which was actively pursuing non-railroad investments in an effort to diversify its sources of income. (In 1968, the Pennsylvania Railroad merged with the New York Central Railroad to form Penn Central Corp.) With the new owners came a more abundant supply of capital for geographic expansion and park additions. Six Flags opened Six Flags Over Georgia in 1967 and Six Flags Over Mid-America in 1971, which would, along with Six Flags Over Texas, be the only three parks that would be constructed by the company.

The company continued to grow by acquiring independent parks. Six Flags purchased AstroWorld in Houston, Texas in 1975, Great Adventure in Jackson, New Jersey in 1977 and Magic Mountain in Valencia, California in 1979. These purchases were followed by Penn Central selling assets to Bally Manufacturing in 1982.

In 1984, the Great America theme park in Gurnee, Illinois was acquired from the Marriott hotel chain.

Also in 1984, as a result of its acquisition of Great America, Six Flags acquired the rights to Time Warner/Warner Bros.' Looney Tunes animated characters for use in Six Flags properties. Bally surrendered control of the chain to Wesray Capital Corporation in a 1987 leveraged buyout. Time Warner quickly began to gain more leverage in the company, gaining a 19.5% stake in Six Flags in 1990 and then 50% in 1991, with the remaining shares of the company being split by Blackstone Group and Wertheim Schroder & Company. Time Warner purchased the remaining stake in Six Flags in 1993, changing the company's name from Six Flags Corp. to Six Flags Theme Parks, Inc.

In 1996, Six Flags began to manage Fiesta Texas theme park in San Antonio, Texas and purchased the park from USAA in 1998.

Premier Parks originally operated as the Tierco Group, Inc., an Oklahoma-based real estate company. The company purchased the Frontier City theme park in Oklahoma City in 1982 for $1.2 million, although Tierco had no intention of entering the amusement park business. Company officials described Frontier City as "beat up" and "run down"; they planned to demolish it, subdivide the land, and build a shopping center. However, given an oil bust in Oklahoma, developers lost interest in converting the park into a shopping center. In 1984 Tierco hired Gary Story as general manager of Frontier City and sunk about $13 million into improving the park. As the new head of Frontier City, he quadrupled the park's attendance and revenues. Under his leadership, two rides, a ticket booth, sales office, and a petting zoo were added to the park. Food service improved.

In 1988, Tierco shifted its strategic direction to amusement parks. It sold much of its property in the late 1980s, generating capital to reinvest in Frontier City. As this reinvestment paid off, more capital became available, creating further growth. By 1991, Tierco opened White Water waterpark in Oklahoma City (the name later became White Water Bay). The company realized the key to boosting a park's attendance was to add new and exciting rides, and make it family-friendly.

Tierco acquired the financially troubled Wild World in Largo, Maryland, in 1992 and later changed that park's name to Adventure World. With a $500,000 investment, Tierco expanded Wild World's kiddie section and remodeled its buildings to give the park a tropical look and feel. Story was promoted to executive vice president after the purchase of Wild World. In 1994, he was promoted again to president and chief operating officer (COO). More flat rides and two roller coasters were added to that park.

Since Tierco was on its way to becoming a "premier" regional theme park operator, in 1994 it changed its name to Premier Parks, Inc. Kieran E. Burke, chairman and chief executive officer (CEO), noted that the new name signified the beginning of a new era for the company.

In the second half of the 1990s, Premier picked up speed. In 1995, the company acquired these Funtime Parks, Inc. properties: Geauga Lake near Cleveland, Ohio, Wyandot Lake in Powell, Ohio, Darien Lake near Buffalo, New York, and Lake Compounce in Bristol, Connecticut. In 1996, Premier added to its portfolio, buying Elitch Gardens in Denver, Colorado, the Waterworld USA waterparks in Sacramento and Concord, California, Riverside Park in Agawam, Massachusetts, and Great Escape and Splashwater Kingdom in Lake George, New York. Premier immediately sold the Lake Compounce park to Kennywood in Pennsylvania.

Geauga Lake, Wyandot Lake, and Adventure World included water parks, while Frontier City was 14.8 miles away from White Water Bay that required separate admission. Riverside added one just before being sold. Premier Parks, in 1995 and 1996, added water parks to Darien Lake, Lake Compounce (immediately before the Kennywood sale), Elitch Gardens, and Great Escape.

Premier went public in 1996 and raised nearly $70 million through an initial offering at $18 per share. The company planned to use the money to expand its ten parks and acquire others. In 1997, Premier purchased Kentucky Kingdom in Louisville, and Marine World near San Francisco. A second public offering, at $29 per share, raised an additional $2 million.

Nearly 8.8 million people visited Premier's parks in 1996.

Premier added amusement park rides and roller coasters to Marine World in 1998.

Six Flags Theme Parks, Inc. was purchased in whole on April 1, 1998 from Time Warner by Premier Parks for $1.86 billion. Premier began to apply the Six Flags name to several smaller parks that the company had already owned: Darien Lake, Elitch Gardens, Kentucky Kingdom, and Adventure World.

In 1999, Premier Parks purchased Warner Bros. Movie World Germany and the yet-to-be-built Warner Bros. Movie World Madrid from Warner Bros.. As part of the acquisition Premier Parks had the opportunity to open more European theme parks with Warner Bros. Movie World branding. Warner Bros. Movie World on the Gold Coast, Australia was not part of the deal. The same transaction saw Premier Parks obtain exclusive rights for Warner Bros. licensing in Europe and Latin America, in addition to their existing rights for the United States and Canada.

In 2000, Premier Parks assumed the Six Flags Theme Parks, Inc. name and continued re-branding its parks, including the Geauga Lake park into Six Flags Ohio and Riverside Park to Six Flags New England. Six Flags began a vigorous expansion, attempting to branch out internationally, acquiring numerous properties across the USA, plus the Walibi chain, and the historic Belgian park Bellewaerde in Europe, La Ronde in Montreal, Quebec, Canada, and Reino Aventura in Mexico. Three of those parks were re-branded as Six Flags parks: Walibi Flevo became Six Flags Holland, Walibi Wavre became Six Flags Belgium, and Reino Aventura became Six Flags Mexico.

In 2001, Six Flags acquired the former SeaWorld Ohio from Anheuser-Busch, merged it with the adjacent Six Flags Ohio and re-branded the combined park as Six Flags Worlds of Adventure. The park was positioned to compete against northern Ohio's Cedar Point.

In 2004, Six Flags began to close and sell properties in an effort to help alleviate the company's growing debt. On March 10, Six Flags sold its European parks, with the exception of the Movie World park in Madrid, Spain, to Star Parks, a division of Palamon Capital Partners. The Madrid park was sold back to Time Warner and renamed "Parque Warner Madrid". In April, Six Flags determined that the investment required to keep Worlds of Adventure competitive with Cedar Point would be too great, leading to that park being sold to Cedar Fair. These sales raised $345 million in an effort to relieve Six Flags' massive debt.

In 2005, Six Flags endured even more turmoil. Some of the company's largest investors, notably Bill Gates's Cascade Investments (which then owned about 11% of Six Flags) and Daniel Snyder's Red Zone, LLC (which owned 12%), demanded change. On August 17, 2005, Red Zone began a proxy battle to gain control of Six Flags' board of directors. On August 29, Six Flags New Orleans was severely damaged by Hurricane Katrina.

On September 12, Six Flags Chief Executive Officer Kieran Burke announced that Six Flags AstroWorld would be closed and demolished at the end of the 2005 season. The company cited issues such as the park's performance, and parking issues involving the Houston Texans football team, Reliant Stadium, and the Houston Livestock Show and Rodeo, leveraged with the estimated value of the property which included the park. Company executives were expecting to receive upwards of $150 million for the real estate, but ended up receiving $77 million when the bare property (which cost $20 million to clear) was sold to a development corporation in 2006.

On November 22, Red Zone announced it had gained control of the board. Kieran Burke was removed on December 14 and replaced by Mark Shapiro, former Executive Vice President of Programming at ESPN. Six Flags then named former Representative Jack Kemp, entertainment mogul Harvey Weinstein, and Michael Kassan, the former president of the Interpublic Group of Companies Incorporated, to their newly revamped board of directors.

Even with the new management team, the sell-off would continue into 2006. On January 27, Six Flags announced the sale of Frontier City and White Water Bay after the 2006 operating season. At the same time, Six Flags announced it would close corporate offices in Oklahoma City, moving its headquarters to New York City. Six Flags CEO Mark Shapiro said he expected the parks to continue operation after the sale, a lesson the company learned after its public relations debacle with the closure of AstroWorld. In June, Six Flags announced it was considering closing or selling up to six of its parks, including Elitch Gardens, Darien Lake, WaterWorld in (Concord, California), Wild Waves and Enchanted Village in Federal Way, Washington, Splashtown in Houston, Texas and, most notably, Six Flags Magic Mountain. In addition, Six Flags announced the sale of Wyandot Lake in Powell, Ohio to the neighboring Columbus Zoo and Aquarium. Ultimately, Six Flags Magic Mountain was spared, with the remaining six parks sold on January 11, 2007 to CNL Lifestyle Properties for $312 million: $275 million cash and a note for $37 million.

The company's cash flow had decreased by over $120 million annually during the Shapiro years. In October 2008, Six Flags was warned its stock value had fallen below the required minimums to remain listed on the New York Stock Exchange. With the financial crisis of 2007–08 weighing both on consumer spending and the ability to access credit facilities, Six Flags was believed to be unable to make a payment to preferred stockholders due in August 2009. Management saw the business as a sound one, noting that attendance across the company's parks increased slightly in 2008 compared to 2007. Six Flags CEO Mark Shapiro said that the company's problem was the declining attendance and cash flow created by his new management initiatives . If not resolved, the company warned in its 2008 annual report that the situation might require a Chapter 11 bankruptcy filing, with Six Flags already retaining counsel should that occur. The company stated at the time that it expected business to continue as normal in the event of such a filing, although one analyst believed attendance at the company's parks would decrease by six percent, suggesting parents would be leery of letting their children ride a roller coaster operated by a bankrupt company. In April 2009, the New York Stock Exchange announced it would delist Six Flags' stock on April 20, a decision that the company did not intend to appeal. On June 1, 2009, Six Flags announced they would delay their $15 million debt payment further using a 30-day grace period. Less than two weeks later, on June 13, the firm filed for Chapter 11 bankruptcy protection, but issued a statement that the parks would continue to operate normally while the company restructured. On August 21, 2009, Six Flags' Chapter 11 restructuring plan was announced in which lenders would control 92% of the company in exchange for cancelling $1.13 billion in debt.

One component of the restructuring was negotiating a new lease agreement with the Kentucky State Fair Board, which owned much of the land and attractions for Six Flags Kentucky Kingdom. Six Flags had asked to forgo rent payments for the remaining nine years of its current lease agreement in exchange for profit-sharing from the park's operations. When it appeared that the offer had been rejected, Six Flags announced in February 2010 that it would not re-open the park. However, the Kentucky State Fair Board stated at the time that they were still open to negotiating a revised lease agreement.

On April 28, 2010, the company's bondholders reached an agreement on a reorganization plan. Junior note holders, including hedge funds Stark Investments and Pentwater Capital Management, assumed control of the company, while senior note holders were paid in cash. Despite objections from some parties who stood to gain nothing, the bankruptcy judge approved the plan on April 30, 2010. As part of the settlement, Chairman of the Board Dan Snyder was removed, while Chief Executive Officer Mark Shapiro briefly remained in his post.

Six Flags officially emerged from bankruptcy protection as Six Flags Entertainment Corp. on May 3, 2010, and announced plans to issue new stock on the New York Stock Exchange. Amid suspected disagreements regarding the future of the company with the board, Shapiro left the company and Al Weber, Jr. was brought in as interim President and CEO. The company announced their corporate headquarters would move from New York City to Grand Prairie, Texas.

Six Flags announced that Jim Reid-Anderson would replace Weber and become Chairman, President and chief executive officer (CEO) on August 13, 2010. John Duffey also joined the company in 2010, taking the role of chief financial officer (CFO). As of October 1, 2012, Al Weber, Jr. had retired as chief operating officer (COO) with no immediate successor.

On February 18, 2016, Six Flags announced that Jim Reid-Anderson had been promoted as Executive Chairman and John M. Duffey succeeded him as President and CEO.

On January 11, 2016, Six Flags announced Six Flags Zhejiang, then named Six Flags Haiyan, in China. On the same day, a website was created along with concept art for the property. A month later on February 2, 2016. Six Flags announced Six Flags Hurricane Harbor Oaxtepec. The water park, originally named Parque Acuatico Oaxtepec, is a 76-acre park located in Morelos that went bankrupt in 2011.

On March 21, 2016, Six Flags announced a partnership with NaVi Entertainment to build a Six Flags-branded theme park and a Six Flags Hurricane Harbor-branded water park in Vietnam.

On March 29, 2016, Six Flags announced the revival of its previously cancelled Six Flags Dubai. As part of the second phase of the Dubai Parks and Resorts project in Jebel Ali, the park is expected to open in 2019.

On July 20, 2016, Six Flags announced an agreement with Riverside Investment Group Co. Ltd. for the development of a second Six Flags-branded theme park in China together with a water park. The two parks will be located in Bishan District, a district of Chongqing.

On April 27, 2017, the company announced it would take over operations of Waterworld California in Concord, California making it Six Flags' 20th property.

On July 18, 2017, Six Flags announced that President and CEO John M. Duffey had retired from the company and Jim Reid-Anderson had re-assumed the roles of Chairman, President, and CEO.

At the flagship Six Flags Over Texas theme park, from 1960 to the mid-1990s, the version of the flag representing the Confederacy was depicted by the rectangular version of the now-inflammatory battle flag. During this time, Civil War re-enactment shows were regularly scheduled at the park, and a variety of different versions of the Confederate flag were used, including the battle flag. However, starting in the 1990s, the Confederate flag depicted was replaced by the lesser-known first national flag of the Confederacy, the "Stars and Bars" with seven stars.

In June 2015, shortly after Dylann Roof A known Democratic supporter killed nine parishioners in Charleston, South Carolina, the park declared they used no variation of the battle flag, either in display nor for sale in shops.

Initially, Six Flags parks would prepare separate marketing campaigns for each park, sometimes with special themes (like the 25th anniversary of Six Flags Great America and the 35th anniversary of Six Flags Over Georgia in 2002).

In 2004, although DC Comics and Looney Tunes as well as Scooby-Doo still had a major presence at the parks, Six Flags began a new series of commercials for the parks. The commercials introduced a new mascot: "Mr. Six", a seemingly feeble old man in a tuxedo and red bow tie. In many of the commercials, Mr. Six would slowly exit a multi-colored bus, only to start frenetically dancing to the Vengaboys' "We Like to Party". The commercials were an immediate hit and Mr. Six almost instantly became the de facto mascot, and his presence was felt for years after the character was retired. These ads have become widely parodied on the Internet, with faces from other Internet memes being superimposed over Mr. Six's face.

From 2008 to 2010, Six Flags' TV ads consisted of a "Fun-O-Meter" in which the beginning of the ad showed something boring or embarrassing and a man's face judges it "One Flag!" or sometimes " Oh! Two Flags!" Then roller coasters and attractions of Six Flags are shown and says "Six Flags, More Flags, More Fun!" for Six Flags parks. However, the thick accent of the Asian man in the original commercials had drawn criticism for being an offensive caricature. In 2009, the Mr. Six character came back from retirement and replaced the Asian man in Six Flags' ads, still using the Fun-O-Meter. In 2011, Six Flags' TV ads got a brand-new slogan "Go Big! Go Six Flags!" for its theme parks.

Six Flags has licensed its name and its theme park creations to other companies, who have used these assets to create licensed products. One notable such example is the theme park simulation game Roller Coaster Tycoon 2, which featured recreations of Six Flags parks and rides that could be expanded and operated at the player's discretion.

In 2008, Six Flags partnered with Brash Entertainment to create a video game based on the Six Flags parks named Six Flags Fun Park. The game was first released on the Nintendo DS and PC in October 2008. The Wii version was delayed after Brash Entertainment went out of business and so the rights were taken over by Ubisoft and released the game on the Wii in March 2009. The game allows players to explore the themed areas and mini-games representative of a visit to a Six Flags park. In the game, players are tasked with quests that encourage them to explore the park's universe. After creating a unique custom character, Six Flags Fun Park patrons can win prizes, and compete with other players in 40 mini-games. Although the video game is called Six Flags Fun Park, it lacks any major reference of Six Flags outside of the names of the different areas. This caused some to speculate that the video game was created separately, then the rights to the name of the game were sold as a way to pay for the game's development. When the game was released, it eventually ended up getting abysmal ratings across the board. IGN gave the Wii version a 4.5 out of 10, saying "The quests are uninteresting and the game's '40 Thrilling Games' (as touted by the box) are far from entertaining."

In recent years, Six Flags has created strategic partnerships with other companies who would feature their products inside the parks. On March 30, 2006, Six Flags announced that it will sell no other pizza besides Papa John's at its parks. In turn, Six Flags will receive an annual sponsorship and promotional opportunities from Papa John's, though financial details of the deal have not been disclosed. However, in the 2011 season, it was replaced by another pizza brand. Other recent partners have included Cold Stone Creamery, Johnny Rockets, Tyson Foods (chicken), Chrysler, and Nintendo, which added testing stations in several parks to show off its Wii console.

In late 2010, Six Flags began the process of removing Non-WB licensed theming from attractions. They terminated licenses with Thomas the Tank Engine, The Wiggles, Tony Hawk, Evel Knievel, and Terminator. However, since then there has been an expansion of licensing agreements with Warner Bros., with whom the company park has had a long-standing relationship with. The expansion lies specifically with Warner Bros. DC Comics brand, where the two teamed up to create the innovative Justice League: Battle for Metropolis as well as many other roller coasters and other rides.

On May 18, 2017, Six Flags and Riverside Group signed an agreement with Paws, Inc. to use Garfield in children's areas in Six Flags-branded theme parks in China.

On June 19, 2007, Six Flags announced it had purchased 40% of Dick Clark Productions, which owns rights to American Bandstand and other shows and productions.

In 2012, Jim Reid-Anderson stated that the company would sell its stake in Dick Clark Productions.

These properties are listed in alphabetical order by the final name of the park while under Six Flags control.

This park includes Six Flags Splashwater Kingdom water park, which opened in 1992. In February 2010, Six Flags announced it would close the park due to a dispute with the Kentucky State Fair Board, from which Six Flags leased much of the park's land area and attractions. In 2014, Kentucky Kingdom reopened under new management.

It was closed after severe damage from Hurricane Katrina in 2005. The city of New Orleans sued Six Flags in 2009 for not making progress to re-open and for not making required lease payments; ultimately, the site was turned over to the city along with a cash payment. In 2011, the city made plans to auction the site and all remaining rides and equipment.