Wicked (known in full as Wicked: The Untold Story of the Witches of Oz) is a musical with music and lyrics by Stephen Schwartz and a book by Winnie Holzman. It is loosely adapted from Gregory Maguire's 1995 novel Wicked: The Life and Times of the Wicked Witch of the West, which itself was based on L. Frank Baum's 1900 novel The Wonderful Wizard of Oz and its 1939 film adaptation. Set in the Land of Oz before and after Dorothy Gale's arrival from Kansas, the musical explores the complex relationship between Elphaba Thropp and Galinda Upland — the future Wicked Witch of the West and Glinda the Good, respectively — as they are tested by their contrasting perspectives, shared love interest, and reactions to the Wizard's corrupt rule, culminating in Elphaba's tragic fall.

Produced by Universal Stage Productions with producers Marc Platt, Jon B. Platt and David Stone, director Joe Mantello and choreographer Wayne Cilento, the original production of Wicked premiered on Broadway at the Gershwin Theatre in October 2003, after completing pre-Broadway tryouts at San Francisco's Curran Theatre in May and June of that year. Its original stars included Idina Menzel as Elphaba, Kristin Chenoweth as Galinda, Norbert Leo Butz as Fiyero, and Joel Grey as the Wizard. Despite mixed reviews, the production won three Tony Awards and seven Drama Desk Awards, while its original cast album received a Grammy Award.

Long-running productions of Wicked include a West End production at the Apollo Victoria Theatre that has played over 7,407 performances, as well as multiple North American tours since 2005. The musical has broken several weekly box-office records around the world; in January 2011, the Broadway, London, and North American touring productions simultaneously broke their respective records for the highest weekly gross. In the final week of 2024, the Broadway production became the first to earn over US$5 million in a single week. Wicked surpassed $1 billion in total Broadway revenue in 2016, joining The Phantom of the Opera and The Lion King as the only shows to do so, and surpassed The Phantom of the Opera by 2017 to become Broadway's second-highest grossing musical, trailing only The Lion King.

A two-part film adaptation was directed by Jon M. Chu and starred Cynthia Erivo as Elphaba, Ariana Grande as Glinda, Jonathan Bailey as Fiyero, and Jeff Goldblum as the Wizard. The first part, featuring extended cameos by Menzel and Chenoweth, was released on November 22, 2024, and was nominated for the Academy Award for Best Picture among numerous other accolades. The second part, Wicked: For Good, was released on November 21, 2025.

Composer and lyricist Stephen Schwartz discovered Gregory Maguire's 1995 novel Wicked: The Life and Times of the Wicked Witch of the West while on vacation and saw its potential for a dramatic adaptation. However, Maguire had released the rights to Universal Pictures, which had planned to develop a live-action feature film. In 1998, Schwartz persuaded Maguire to release the rights to a stage production while also making what Schwartz himself called an "impassioned plea" to Universal producer Marc Platt to realize Schwartz's own intended adaptation. Persuaded, Platt signed on as joint producer of the project with Universal and David Stone.

The novel, described as a political, social, and ethical commentary on the nature of good and evil, takes place in the Land of Oz, in the years surrounding Dorothy's arrival. The story centers on Elphaba, a misunderstood, smart, and fiery girl with emerald-green skin, who grows up to become the Wicked Witch of the West, and Galinda, the beautiful, blonde, popular girl who grows up to become Glinda the Good. The story is divided into five scenes, based on the locations where Elphaba lives during her life; it presents events, characters, and situations adapted from L. Frank Baum's The Wonderful Wizard of Oz (1900) and its 1939 film adaptation. The novel addresses some serious and dark adult themes, including sexual assault, political unrest, infidelity, racism and the role of religion in society. It prompts the reader to think about what it really is to be "Wicked", and whether good intentions with bad results are the same as bad intentions with bad results. Schwartz considered how best to condense the novel's dense and complicated plot into a sensible script. To this end, he collaborated with writer Winnie Holzman to develop the outline of the plot over the course of a year, while meeting with producer Marc Platt to refine the structural outline of the show, creating an original stage piece rather than a strict adaptation of Maguire's work.

While the draft followed Maguire's idea of retelling the story of the 1939 film from the perspective of its main villain, the storyline of the stage adaptation "goes far afield" from the novel. Holzman observed in an interview with Playbill that: "It was [Maguire's] brilliant idea to take this hated figure and tell things from her point of view, and to have the two witches be roommates in college, but the way in which their friendship develops—and really the whole plot—is different onstage." Schwartz justified the deviation, saying: "Primarily we were interested in the relationship between Galinda—who becomes Glinda—and Elphaba... the friendship of these two women and how their characters lead them to completely different destinies." Other major plot modifications include Fiyero's appearance as the Scarecrow, Elphaba's survival at the end, Nessarose using a wheelchair instead of being born without arms, Boq having a continuing love interest for Glinda and eventually becoming the Tin Woodman instead of Nick Chopper, cutting Elphaba's years in the Vinkus, the deletion of Liir's birth, Fiyero not having a wife and children, Doctor Dillamond being fired instead of being murdered, and Madame Morrible going to prison instead of dying.

The book, lyrics, and score for the musical were developed through a series of readings. In these developmental workshops, Kristin Chenoweth, the actress whom Schwartz had in mind while composing the music for the character, joined the project as Glinda. Stephanie J. Block played Elphaba in the workshops (she played Elphaba in the first national tour and later as a Broadway cast replacement) before Idina Menzel was cast in the role in late 2002. Earlier that year, the creators recruited New York producer Stone, who began planning the Broadway production. Joe Mantello was engaged as director and Wayne Cilento as choreographer, while designer Eugene Lee created the set and visual style for the production inspired by W. W. Denslow's original illustrations for Baum's novels and Maguire's concept of the story being told through a giant clock. Costume designer Susan Hilferty created a "twisted Edwardian" style in building more than 200 costumes, while lighting designer Kenneth Posner used more than 800 lights to give each of the 54 distinct scenes and locations "its own mood". By April 2003, the show was in rehearsals.