The idea of a live-action Barbie film was in development at Cannon Films in the mid-1980s. Renewed development on a film based on the Barbie toy line began in September 2009, when it was announced that Mattel had signed a partnership with Universal Pictures and producer Laurence Mark, but nothing came to fruition. In April 2014, Mattel teamed with Sony Pictures to produce the film, which would have Jenny Bicks writing the screenplay and Laurie MacDonald and Walter F. Parkes producing through their Parkes+MacDonald Image Nation banner. Filming was anticipated to begin by the end of the year. In March 2015, Diablo Cody was brought onto the project to rewrite the screenplay, and Amy Pascal joined the producing team.
In December 2016, Amy Schumer entered negotiations for the title role with Winston's screenplay. She helped rewrite the script with her sister, Kim Caramele. In March 2017, she exited negotiations, initially saying it was due to scheduling conflicts with the planned June 2017 filming; she revealed in 2023 that she left due to creative differences with the film's producers. That July, Anne Hathaway was considered for the title role; Sony hired Olivia Milch to rewrite the screenplay and approached Alethea Jones to direct as a means of interesting Hathaway in signing. Jones was attached to direct by March 2018.
In August 2018, Mattel CEO Ynon Kreiz hired film executive Robbie Brenner, who was later appointed head of Mattel Films. Sony's option on the project expired in October 2018, and film rights were transferred to Warner Bros. Pictures, causing Hathaway, Jones, Macdonald, Parkes and Pascal to leave them project.
Margot Robbie entered early talks for the role, and Patty Jenkins was briefly considered as director. Kreiz was determined to cast Robbie after meeting with her; both he and Brenner felt that Robbie's appearance resembled that of a conventional Barbie doll and were impressed by her ideas. Initial meetings occurred at the Polo Lounge located in The Beverly Hills Hotel. Brenner eventually partnered with Robbie's production company, LuckyChap Entertainment, and Robbie's husband Tom Ackerley and Josey McNamara were enlisted as producers. Robbie's casting was confirmed in July 2019.
In her capacity as a producer, Robbie pitched Barbie to Warner Bros. herself. During the green-light meeting, she compared the film to Steven Spielberg's Jurassic Park (1993) and also jokingly suggested that it would gross over $1 billion. Later on, she approached Greta Gerwig—whose previous films, particularly Little Women (2019), Robbie enjoyed—to screenwrite. Gerwig was in post-production for another film, and took the assignment on the condition that her partner, Noah Baumbach, also write the script. Gerwig would sign on to also direct the film in July 2021. Robbie said the film aimed at subverting expectations and giving audiences "the thing you didn't know you wanted."
As writers, Gerwig and Baumbach were given full creative freedom. They worked on the screenplay during the 2020-2021 COVID-19 pandemic lockdowns at their house in Long Island. Baumbach felt he understood the film's purpose once Gerwig had shown him the first scene, identifying the "element" as "embracing mortality and sadness and sickness and everything that it means to be human." Gerwig was also inspired by the real-life story of Barbie creator Ruth Handler. Gerwig's film treatment consisted of an abstract poem on Barbie influenced by the Apostles' Creed. For the narrative arc, she was partially inspired by the non-fiction book Reviving Ophelia (1994) by Mary Pipher, which accounts the effects of societal pressures on American teenage girls. She also found inspiration in classic Technicolor musicals such as The Red Shoes (1948) and The Umbrellas of Cherbourg (1964), and said: "They have such a high level of what we came to call authentic artificiality. You have a painted sky in a soundstage. Which is an illusion, but it's also really there. The painted backdrop is really there. The tangibility of the artifice is something that we kept going back to." The script also contains candid criticism of Mattel, which created skepticism among Mattel officials when they received the first version. However, Kreiz decided to trust Gerwig. Brenner noted that "being safe in this world doesn't work" as she interpreted Barbie to be a "bold" and "trailblazer" figure. As a result, Will Ferrell's portrayal as the Mattel CEO was meant to be an allegory for corporate America. Kreiz praised Ferrell and said that while Mattel officials took their brands seriously, they did not take themselves seriously. Gerwig and Robbie had felt the film was "most certainly a feminist film", but Mattel officials rejected the description. Gerwig and Robbie informed the studio that they would explore the controversies and problematic parts of Barbie, but also convinced the studio that they would respect the product.
Greta Gerwig (Clement Pascal for The New York Times)
Gerwig was also influenced by her childhood experiences with Barbie. Her mother discouraged her from purchasing such dolls, but eventually allowed her to. Opting to acknowledge the controversial nature of the Barbie doll, Gerwig chose to create a film where she would be both "doing the thing and subverting the thing", in the sense that she would be celebrating the feminism behind Barbie while also noting the controversial beauty standards associated with it. She was also fascinated by the idea that humans created dolls, which in turn imitate humans, feeling that "we're in constant conversation with inanimate objects" while also conveying an affirmative message to the audience to "just be yourself and know that that's enough." The film deliberately juxtaposed contradictory messaging, such as critiquing consumerism yet glamorizing plastic products; and in the film's ending, where Barbie desires to be more than just a plastic doll. Gerwig made the film as an "earnest attempt to make amends" between affirming womens' worth and conveying the impossibility of perfection, which some perceived to be standards associated with Barbie.
Reflecting upon the maximalism of Barbie, Gerwig said the "ontology of Barbie" was similar to what she perceived as William Shakespeare's maximalism, which she enjoyed in his works. She grounded the film in what she described as a "heightened theatricality that allows you to deal with big ideas in the midst of anarchic play." She also described the film as being anarchic, unhinged, and humanist. She felt the film originated from the "deep isolation of the pandemic", opining that the line in which Barbie says "Do you guys ever think about dying?" exemplifies the film's anarchic nature. She also found the idea of Barbie being "constrained in multitudes" as "all of these women are Barbie and Barbie is all of these women" to be "trippy" and felt as a result, Barbie did not need to have her own personal life, as she was attuned to her environment. She also described the story as mirroring a girl's journey from childhood to adolescence, though she did not deem it to be a coming of age film and felt that the film ultimately "ends up, really, about being human."
Primarily, she began her writing by interpreting Barbie as living in a utopia and eventually experiencing reality, where she would have to "confront all the things that were shielded from them in this place [Barbieland]." She also drew parallels to the story of Adam and Eve and taking inspiration from John Milton's Paradise Lost, particularly being inspired by the concept that there is "no poetry without pain." To underscore the tragic elements of Barbie and Ken facing the real world, she focused on elements of dissonance. As such, she chose to keep a scene featuring Robbie's Barbie telling an older woman that she is beautiful after being requested to remove it, as she felt that the scene epitomized "the heart of the movie." She also desired to provide a "counterargument" to Barbie by featuring a scene in which Barbie learns that some women do not like her, and felt it gave the film "real intellectual and emotional power." As such, a scene is featured in which Barbie is being stared at inappropriately on the Venice Beach, which Gerwig chose to feature as she felt it was a universal experience, being especially relevant for actors. She was inspired by an audition she did in which she wore overalls and felt that she did not perform well in.
The ending of the film features Barbie saying the line "I'm here to see my gynecologist", with Gerwig describing it as a "mic drop kind of joke." She had chosen to include the line as she had wanted to instill confidence in younger girls, as she had been embarrassed about her body when she was younger. Barbie also explores the negative consequences of hierarchical power structures, with Gerwig saying that she extrapolated that "Barbies rule and Kens are an underclass" and felt it was similar to the Planet of the Apes. Ken has low self-esteem and seeks approval from Barbie, which Gerwig identified as a good source for a story. Gosling compared Gerwig's vision to Milton Glaser's I Love New York logo as he felt Gerwig created the film's characters as a way of understanding the contemporary world. Ken has the only power ballad in the film, and Gerwig had identified it as the moment in which she felt the film transcended what a Barbie film traditionally should have been.