The Oblonsky family of Moscow is torn apart by adultery. Dolly Oblonskaya has caught her husband, Stiva, having an affair with their children’s former governess, and threatens to leave him. Stiva is somewhat remorseful but mostly dazed and uncomprehending. Stiva’s sister, Anna Karenina, wife of the St. Petersburg government official Karenin, arrives at the Oblonskys’ to mediate. Eventually, Anna is able to bring Stiva and Dolly to a reconciliation.
Meanwhile, Dolly’s younger sister, Kitty, is courted by two suitors: Konstantin Levin, an awkward landowner, and Alexei Vronsky, a dashing military man. Kitty turns down Levin in favor of Vronsky, but not long after, Vronsky meets Anna Karenina and falls in love with her instead of Kitty. The devastated Kitty falls ill. Levin, depressed after having been rejected by Kitty, withdraws to his estate in the country. Anna returns to St. Petersburg, reflecting on her infatuation with Vronsky, but when she arrives home she dismisses it as a fleeting crush.
Vronsky, however, follows Anna to St. Petersburg, and their mutual attraction intensifies as Anna begins to mix with the freethinking social set of Vronsky’s cousin Betsy Tverskaya. At a party, Anna implores Vronsky to ask Kitty’s forgiveness; in response, he tells Anna that he loves her. Karenin goes home from the party alone, sensing that something is amiss. He speaks to Anna later that night about his suspicions regarding her and Vronsky, but she curtly dismisses his concerns.
Some time later, Vronsky participates in a military officers’ horse race. Though an accomplished horseman, he makes an error during the race, inadvertently breaking his horse’s back. Karenin notices his wife’s intense interest in Vronsky during the race. He confronts Anna afterward, and she candidly admits to Karenin that she is having an affair and that she loves Vronsky. Karenin is stunned.
Kitty, meanwhile, attempts to recover her health at a spa in Germany, where she meets a pious Russian woman and her do-gooder protégée, Varenka. Kitty also meets Levin’s sickly brother Nikolai, who is also recovering at the spa.
Levin’s intellectual half-brother, Sergei Koznyshev, visits Levin in the country and criticizes him for quitting his post on the local administrative council. Levin explains that he resigned because he found the work bureaucratic and useless. Levin works enthusiastically with the peasants on his estate but is frustrated by their resistance to agricultural innovations. He visits Dolly, who tempts him with talk of reviving a relationship with Kitty. Later, Levin meets Kitty at a dinner party at the Oblonsky household, and the two feel their mutual love. They become engaged and marry.
Karenin rejects Anna’s request for a divorce. He insists that they maintain outward appearances by staying together. Anna moves to the family’s country home, however, away from her husband. She encounters Vronsky often, but their relationship becomes clouded after Anna reveals she is pregnant. Vronsky considers resigning his military post, but his old ambitions prevent him.
Karenin, catching Vronsky at the Karenin country home one day, finally agrees to divorce. Anna, in her childbirth agony, begs for Karenin’s forgiveness, and he suddenly grants it. He leaves the divorce decision in her hands, but she resents his generosity and does not ask for a divorce. Instead, Anna and Vronsky go to Italy, where they lead an aimless existence. Eventually, the two return to Russia, where Anna is spurned by society, which considers her adultery disgraceful. Anna and Vronsky withdraw into seclusion, though Anna dares a birthday visit to her young son at Karenin’s home. She begins to feel great jealousy for Vronsky, resenting the fact that he is free to participate in society while she is housebound and scorned.
Married life brings surprises for Levin, including his sudden lack of freedom. When Levin is called away to visit his dying brother Nikolai, Kitty sparks a quarrel by insisting on accompanying him. Levin finally allows her to join him. Ironically, Kitty is more helpful to the dying Nikolai than Levin is, greatly comforting him in his final days.
Kitty discovers she is pregnant. Dolly and her family join Levin and Kitty at Levin’s country estate for the summer. At one point, Stiva visits, bringing along a friend, Veslovsky, who irks Levin by flirting with Kitty. Levin finally asks Veslovsky to leave. Dolly decides to visit Anna, and finds her radiant and seemingly very happy. Dolly is impressed by Anna’s luxurious country home but disturbed by Anna’s dependence on sedatives to sleep. Anna still awaits a divorce.
Levin and Kitty move to Moscow to await the birth of their baby, and they are astonished at the expenses of city life. Levin makes a trip to the provinces to take part in important local elections, in which the vote brings a victory for the young liberals. One day, Stiva takes Levin to visit Anna, whom Levin has never met. Anna enchants Levin, but her success in pleasing Levin only fuels her resentment toward Vronsky. She grows paranoid that Vronsky no longer loves her. Meanwhile, Kitty enters labor and bears a son. Levin is confused by the conflicting emotions he feels toward the infant. Stiva goes to St. Petersburg to seek a cushy job and to beg Karenin to grant Anna the divorce he once promised her. Karenin, following the advice of a questionable French psychic, refuses.
Anna picks a quarrel with Vronsky, accusing him of putting his mother before her and unfairly postponing plans to go to the country. Vronsky tries to be accommodating, but Anna remains angry. When Vronsky leaves on an errand, Anna is tormented. She sends him a telegram urgently calling him home, followed by a profusely apologetic note. In desperation, Anna drives to Dolly’s to say goodbye, and then returns home. She resolves to meet Vronsky at the train station after his errand, and she rides to the station in a stupor. At the station, despairing and dazed by the crowds, Anna throws herself under a train and dies.
Two months later, Sergei’s book has finally been published, to virtually no acclaim. Sergei represses his disappointment by joining a patriotic upsurge of Russian support for Slavic peoples attempting to free themselves from Turkish rule. Sergei, Vronsky, and others board a train for Serbia to assist in the cause. Levin is skeptical of the Slavic cause, however.
Kitty becomes worried by Levin’s gloomy mood. He has become immersed in questions about the meaning of life but feels unable to answer them. One day, however, a peasant remarks to Levin that the point of life is not to fill one’s belly but to serve God and goodness. Levin receives this advice as gospel, and his life is suddenly transformed by faith.
Later that day, Levin, Dolly, and Dolly’s children seek shelter from a sudden, violent thunderstorm, only to discover that Kitty and Levin’s young son are still outside. Levin runs to the woods and sees a huge oak felled by lightning. He fears the worst, but his wife and child are safe. For the first time, Levin feels real love for his son, and Kitty is pleased. Levin reflects again that the meaning of his life lies in the good that he can put into it.