Anna Karenina is a novel by the Russian writer Leo Tolstoy, published in serial instalments from 1873 to 1877 in the periodical The Russian Messenger. Tolstoy clashed with Editor Mikhail Katkov over political issues that arose in the final instalment (Tolstoy's unpopular views of volunteers going to Serbia); therefore, the novel's first complete appearance was in book form. Widely regarded as a pinnacle in realist fiction, Tolstoy considered Anna Karenina his first true novel, when he came to consider War and Peace to be more than a novel.

Fyodor Dostoevsky declared it to be "flawless as a work of art". His opinion was shared by Vladimir Nabokov, who especially admired "the flawless magic of Tolstoy's style", and by William Faulkner, who described the novel as "the best ever written”. The novel is currently enjoying popularity, as demonstrated by a recent poll of 125 contemporary authors by J. Peder Zane, published in 2007 in "The Top Ten" in Time, which declared that Anna Karenina is the "greatest novel ever written".

Anna Karenina is the tragedy of married aristocrat and socialite Anna Karenina and her affair with the affluent Count Vronsky. The novel is divided into eight parts. Tolstoy's style in Anna Karenina is considered by many critics to be transitional, forming a bridge between the realist and modernist novel. The novel is narrated from a third-person-omniscient perspective, shifting the narrator's attention to several major characters, though most frequently focusing on the opposing lifestyles and attitudes of its central protagonists of Anna and Levin.