The story of The Lion King takes place in the Pride Lands, where a lion rules over the other animals as king.
At the beginning of the film, Rafiki (Robert Guillame), a mandrill shaman, anoints Simba, the newborn cub of King Mufasa (James Earl Jones) and Queen Sarabi (Madge Sinclair), and presents him to a gathering of animals at Pride Rock ("The Circle of Life"). Meanwhile, Mufasa's younger brother, Scar (Jeremy Irons), realizes that he is no longer the heir to the throne and plots to kill Simba.
Mufasa takes Simba (Jonathan Taylor Thomas) around the Pride Lands, teaching him about the "Circle of Life", the delicate balance affecting all living things. Later, Scar tells Simba about the elephant graveyard, a place where Mufasa has warned him not to go. Simba asks his mother if he can go to the water-hole with his best friend, Nala (Niketa Calame). Their parents agree, but only if Mufasa's majordomo, the hornbill Zazu (Rowan Atkinson), goes with them. Simba and Nala elude Zazu's supervision ("I Just Can't Wait to Be King") and go to the graveyard instead. There, the cubs are chased by Shenzi, Banzai and Ed (Whoopi Goldberg, Cheech Martin and Jim Cummings), Scar's spotted hyenas who try to kill them, but are rescued by Mufasa, who was summoned by Zazu.
Meanwhile, Scar gains the loyalty of the hyenas by claiming that if he becomes king, they will "never go hungry again." Plotting further, Scar gathers more hyenas ("Be Prepared") forming an army. Some time later, Scar lures Simba into a gorge for a "surprise from his father" then signals the hyenas create a wildebeest stampede down into the gorge where Simba is. Alerted by an insincerely dramatic Scar, Mufasa races to rescue Simba from the stampede. He saves his son but is left clinging to the edge of a cliff, which results in Scar flinging him into the stampede below, where he is buried into the some of the wildebeests' horns, hit the ground with extreme force, and finally trampled to death by the wildebeest. Scar convinces Simba that he was responsible for his own father's death, and recommends that he flees the Pride Lands, never to return. To compound this, Scar once again sends the hyenas to kill Simba, but as Simba reaches a thorny embankment, they let him escape, hurling threats that he will be killed if ever seen again. Scar informs the pride that both Mufasa and Simba were killed in the stampede, and that he is assuming the throne as the closest of king.
Simba collapses in a distant desert where he is found unconscious by Timon and Pumbaa (Nathan Lane and Ernie Sabella), a meerkat-warthog duo who raise Simba under their carefree "Hakuna Matata" lifestyle ("Hakuna Matata"). When Simba has grown into a young adult (Matthew Broderick) he saves them from a hungry lioness who is revealed to be Nala (Moira Kelly). Simba shows Nala around his home and the two begin to fall in love ("Can You Feel the Love Tonight"). Nala then tells him that Scar's tyrannical reign has turned the Pride Lands into a barren wasteland; she demands that Simba must return and take his rightful place as king, but Simba refuses, still guilty about supposedly causing his father's death. Rafiki arrives and persuades Simba to return to the Pride Lands, aided by Mufasa's presence in the stars. After some advance from Rafiki and the ghost of his father, Simba, followed by Nala, Timon and Pumbaa, returns home.
Once back at Pride Rock, Simba (with Timon, Pumbaa and Nala) is horrified to see the condition of the Pride Lands. After seeing Scar strike his mother, Simba announces his return. In response, Simba confronts Scar and the truth about Mufasa's death which is revealed by an overly confident Scar who forces Simba over the edge of Pride Rock, just as a lighting bolt starts a fire below. As Simba dangles over the edge of Pride Rock, Scar whispers to Simba that he killed Mufasa. Enraged, Simba leaps up and pins Scar to the ground, forcing him to admit the truth to the pride. A raging battle then ensues between the hyenas and the lionesses, Timon, and Pumbaa which results in Simba cornering Scar. In the midst of their fight, Scar tries to surreptitiously blame everything on the hyenas for, but the hyenas overhear his conversation with Simba. Simba orders Scar to flee the Pride Lands. Scar pretends to leave but turns to attack Simba, resulting in a final duel. Simba eventually triumphs over his uncle by flipping him and kicks him over a low cliff. Scar survives the fall but finds himself surrounded by the now resentful hyenas. The hyenas surround their traitorous fallen leader, and attack him and maul him to death, as flames rise around them.
With Scar and the hyenas gone, and with the rightful king in place, the Pride Lands are restored which is turning green with life again. The film concludes with Rafiki presenting Simba and Nala's newborn cub Kiara into the air, thus continuing the Circle of Life.