Scar is a fictional character and the main antagonist of Disney's The Lion King franchise. He is introduced in the 1994 animated film as the younger, envious brother of Mufasa, the ruler of the Pride Lands. Originally first in line to the throne, Scar is abruptly replaced by Mufasa's newborn son, Simba. Enraged, he devises a plot to usurp the throne by leading an army of hyenas and betraying both Mufasa and Simba. After killing Mufasa, Scar manipulates Simba into believing he is to blame, prompting Simba to flee into exile.

Created by screenwriters Irene Mecchi, Jonathan Roberts, and Linda Woolverton, and animated by Andreas Deja, Scar is loosely based on King Claudius, the main antagonist in William Shakespeare's Hamlet. His villainy was further inspired by German dictator Adolf Hitler, as well as by lions' natural behavior of pride takeovers. As the character's supervising animator, Deja modeled Scar's appearance on the original voice actor Jeremy Irons, drawing particularly from Irons's performance as Claus von Bülow in Reversal of Fortune. Chiwetel Ejiofor voices the photorealistic version of Scar in the 2019 remake, while Kelvin Harrison Jr. portrays the character in Mufasa: The Lion King.

As a character, Scar has garnered widespread acclaim from film critics, with Irons's vocal performance receiving universal acclaim. However, his violence, dark color palette and allegedly effeminate mannerisms initially sparked mild controversy. Nevertheless, Scar remains celebrated as one of Disney's greatest villains by various media outlets—topping HuffPost's list and ranking within the top ten of similar lists published by Yahoo! Movies, the Orlando Sentinel, E! and CNN. He has also been recognized among the greatest villains in film history by Digital Spy and Entertainment Weekly.

The Lion King was first conceived in 1988. The film was eventually pitched to Disney executives, one of whom was among the first to observe similarities between author Thomas M. Disch's treatment and William Shakespeare's play Hamlet. Although first citing these similarities as initially unintentional, director Rob Minkoff always felt it was essential "to anchor [the film] with something familiar." As directors, Minkoff and Roger Allers aspired to create "an animal picture based in a more natural setting," describing the film as "More true-life adventure than mythical epic." Although not the first Disney film to have been inspired by Shakespeare's work, The Lion King remains the studio's most prominent example, due to close parallels between its characters and Hamlet, while both stories revolve around main characters who struggle to come to terms with the reality that they must confront their treacherous uncles and avenge their fathers' deaths. Scar is based on King Claudius. According to Slate, while Claudius is mostly "a second-rate schemer, consumed by anxiety and guilt," Scar very much "delight[s] in his monstrosity;" both characters are motivated by jealousy. Meanwhile, The Week observed that although both characters ultimately die, Claudius is killed by protagonist, Prince Hamlet, while Scar dies "at the hand of his former hyena minions, and not Simba, himself." Additionally, the character shares similarities with Iago from Shakespeare's play Othello, as both antagonists are skilled in exploiting their victims' fears.

The original plot of The Lion King revolved around a rivalry between lions and baboons. A baboon himself, Scar was their leader. After this plot was abandoned, Scar was re-written into a rogue lion lacking any blood relation to both Mufasa and Simba. Lacking a pride of his own, he simply wanted what Mufasa had. The writers eventually decided that making Scar and Mufasa brothers would make the film more interesting. At one point, Scar owned a pet python as a sidekick, but this character was abandoned. Because the film was originally intended to be much more adult-oriented, Scar was to have become infatuated with Simba's childhood friend and eventual love interest, Nala, wanting the young lioness to rule alongside him as his queen, and consequentially banishing the character when she refuses. This concept was to have been further explored during a reprise of Scar's song "Be Prepared", but both the idea and the song were ultimately removed from the film, because they were deemed too "creepy." In addition to that, there was a scene in which Scar was originally going to defeat Simba and throw him off Pride Rock, before he is engulfed by flames. This ending was cut for being far too dark for young viewers. To further emphasize the character's villainy and tyranny, the writers loosely based Scar on Adolf Hitler. According to The Jerusalem Post, Scar's song "Be Prepared" "features goose-stepping hyenas in a formation reminiscent of a Nuremberg rally." This idea was first suggested by story artist Jorgen Klubien.

According to the directors, "[a] patronizing quality" was vital to Scar's role in the film. Minkoff told the Los Angeles Times, "When Scar puts the guilt trip on Simba, that's an intense idea and probably something that is not typical of the other Disney pictures, in terms of what the villain does." Additionally, Scar serves as a departure from previous Disney Villains, because they "came off at least as buffoonish as they were sinister". Because Scar is the film's main antagonist, supervising animator Andreas Deja believed that "villains work really well when they're subtle," explaining, "to see them think and scheme and plot is much more interesting than showing them beating somebody up." By blaming Mufasa's death on an innocent Simba, Scar ultimately triggers "a cycle of guilt, flight, denial and redemption, as the hero goes into self-imposed exile, before finally reconciling with his father's memory, returning to face his wicked uncle and generally coming of age." The character's first line in The Lion King "essentially summarizes the entire film, providing foreshadowing". It reads, "Life's not fair is it? You see I—well, I shall never be King. And you shall never see light of another day. Adieu," which subtly reveals the plot, as well as "the reason why [Scar] decides to murder his own brother." (This line is given minor edits for the 2019 remake: "Life's not fair. Is it, my little friend? While some are born to feast, others spend their lives in the dark, begging for scraps. The way I see it, you and I are exactly the same: we both want to find a way out.").

Tim Curry, Malcolm McDowell, Alan Rickman, Patrick Stewart, and Ian McKellen were all originally considered for the role of Scar. However, the actor ultimately chosen for the role was Jeremy Irons, because of his classical theater training, because the directors had deliberately wanted Scar "to come across as a Shakespearean character." Successfully recruiting Irons for the film was considered an unprecedented achievement for the studio because, at the time, it was rare for a dramatic actor of Irons's caliber to agree to voice an animated character, especially immediately after winning an Academy Award. Irons nearly declined, because, in fear of jeopardizing his successful career, he was "[h]esitant to jump from a dramatic role to an animated feature." Prior to The Lion King, Irons was famous for starring as several villains and antagonists in live action films "geared towards adults." Although he had starred in a children's film before, the actor admitted that it did not mirror the success of The Lion King, a film that has since gained notoriety for its cast of well known, award-winning Hollywood actors, which animation historian Jerry Beck referred to in his book The Animated Movie Guide as "the most impressive list of actors ever to grace an animated film."

As directors, Minkoff and Allers "work[ed] very closely with the actors to create their performance." Describing Irons as "a gentleman and a brilliant actor," Allers revealed that the actor was constantly offering "extra interpretations of lines which were fantastic." Producer Don Hahn recalled that Irons "really wanted to play with the words and the pacing," specifically referring to a scene in which Scar coaxes Simba onto a rock and tricks the cub to stay there and await his father's arrival, dubbing it "a father and son thing." According to Hahn, "The comedy in [Irons's] inflection comes from Scar sounding so disdainful he can barely summon the will to finish the sentence." Irons's physical appearance and mannerisms served as inspiration for Scar's supervising animator Andreas Deja, namely his flicking his paw in disgust. Critics have cited physical similarities between Irons and Scar.