Monster High is an American multimedia-supported fashion doll franchise created by toy designer Garrett Sander and launched by Mattel in 2010.

The franchise quickly became very popular among children and was extremely successful in terms of earnings for Mattel; it was worth $1 billion in its third year of existence with more than $500 million in sales annually, and was at one point the second best-selling doll brand in North America.

Since the franchise's beginnings in the late 2000s and early 2010s, Monster High has valued diversity among its characters and their visual appearance, personalities, abilities, and cultural backgrounds.

[37] Various other Monster-High-branded products have been released: they include collectible vinyl figurines, Halloween costumes, plushies,[38] stationery, children's clothing, accessories, and makeup, perfume, and more.

[41] Launched in the digital media era, Monster High began adaptation into a web series which had its debut on YouTube on 5 May 2010, followed by a 23-minute TV special, New Ghoul @ School on October 30 that same year which premiered on Nickelodeon in the United States.

were 2D-animated, with the following films animated in CGI or computer animation: "Why Do Ghouls Fall in Love", "Escape from Skull Shores", "Friday Night Frights", "Scaris: City of Frights", "Ghouls Rule", "13 Wishes", "Freaky Fusion", "Haunted", "Boo York, Boo York", Great Scarrier Reef, Welcome to Monster High and Electrified.

The films ranked Monster High as the second in the list of children's direct-to-video franchises that year, according to online magazines and publications.

[44] However, the first franchise reboot and the discontinuation of Ever After High derailed and cancelled those plans (which also included more based-on films than the 16 indicated); brief storyboard animatics were instead released on the official Monster High YouTube channel under the title The Lost Movie[45] and early designs for the EAH characters intended for the crossover have been released online.

[46] In 2021, it was announced that Mattel Television would produce a live-action musical film and an animated TV series for Nickelodeon, which premiered in October 2022.

[47][48] Monster High: Kowa Ike Girls (Japanese: モンスター・ハイ こわイケガールズ, romanized: Monsutā Hai Kowa Ike Gāruzu; Monsutā Hai and Gāruzu being transliteration of "Monster High" and "Girls", respectively) is an 8-episode series of 3-minute Japanese animated shorts produced by Shougakukan Music & Digital Entertainment [ja],[49] and animated at Picona Creative Studio.

[49][50] The shorts were broadcast as a part of TXN's morning children's television programming block Oha Suta beginning on October 22, 2014.

The Monster High website has also released a series of catacomb-themed web games: "trick or trance", "phantom roller" and "scary sweet memories".

Lisi Harrison, a Canadian author known for writing popular book series; The Clique and The Alphas, wrote some young adult novels based on the franchise using a different fictional universe than the web series and deal with the Regular-Attribute Dodgers (RADs) and their struggles with love, social life, school and not to be outed as monsters to humans.

The second book in the series, The Ghoul Next Door, was released at the end of March 2011[54] and features chapters on Cleo de Nile.

Another Monster High book called Drop Dead Diary was released on January 19, 2011; it was written by a pseudonymous author Abaghoul Harris.

[56] Author Gitty Daneshvari has written a Ghoulfriends series focusing on Monster High characters Venus McFlytrap, Robecca Steam, and Rochelle Goyle.

Ever After High (abbreviated EAH) launched in July 2013 and features the children of characters of well-known fairy tales and fables.

Monster High was a massive financial success for Mattel,[82][83][84][85] becoming a billion-dollar brand in just three years and surpassing executives' expectations.

[88] In 2010, shortly after the dolls launched for the first time, they were so popular it was sometimes hard to find them in stores due to scarcity and they were selling out quickly.

[89] The line's success was partially thanks to its appeal to younger children who were choosing to play with toys which were "a little bit edgier" than traditional fashion dolls like Barbie,[90][91] its "anti-bullying message" which encouraged children to be themselves and embrace their own flaws and differences,[92] and the "deep engagement" of fans with the franchise which was maintained through media and merchandise.

[94] The franchise has received positive recognition for its promotion of diversity among the characters, especially in comparison with other toy brands with similar levels of popularity.

"[35] Monster High has some controversy and criticism, citing that the dolls' unrealistic bodies, often revealing outfits, and characters' focus on romantic relationships were a bad influence on young children.

[99][100] They were criticized for being "hyper-sexualized" and reinforcing gender stereotypes about women; it was even implied that children could develop low self-esteem and eating disorders due to the presentation of unattainable body types.

[103] The same year, MGA also launched Novi Stars, a sci-fi-themed line of fashion dolls that featured extraterrestrial humanoids.