Eugene Onegin, A Novel in Verse (Russian: Евгений Онегин, роман в стихах, romanized: Yevgeniy Onegin, roman v stikhakh, pre-reform Russian: Евгеній Онѣгинъ, романъ въ стихахъ, [jɪvˈɡʲenʲɪj ɐˈnʲeɡʲɪn]) is a novel in verse written by Alexander Pushkin. Onegin is considered a classic of Russian literature, and its eponymous protagonist has served as the model for a number of Russian literary heroes (so-called superfluous men). It was published in serial form between 1825 and 1832. The first complete edition was published in 1833, and the currently accepted version is based on the 1837 publication.

Almost the entire work is made up of 389 fourteen-line stanzas (5,446 lines in all) of iambic tetrameter with the unusual rhyme scheme AbAbCCddEffEgg, where the uppercase letters represent feminine rhymes while the lowercase letters represent masculine rhymes. This original structure is known as the "Onegin stanza" or "Pushkin sonnet".

The story is told by a narrator (a lightly fictionalized version of Pushkin's public image), whose tone is educated, worldly, and intimate. The narrator digresses at times, usually to expand on aspects of this social and intellectual world. This narrative style allows for a development of the characters and emphasizes the drama of the plot despite its relative simplicity. The book is admired for the artfulness of its verse narrative as well as for its exploration of life, death, love, ennui, convention, and passion.

In the 1820s, Eugene Onegin is a bored St. Petersburg dandy, whose life consists of balls, concerts, parties, and nothing more. Upon the death of a wealthy uncle, he inherits a substantial fortune and a landed estate. When he moves to the country, he strikes up a friendship with his neighbor, a starry-eyed young poet named Vladimir Lensky. Lensky takes Onegin to dine with the family of his fiancée, the sociable but rather thoughtless Olga Larina. At this meeting, he also catches a glimpse of Olga's sister Tatyana. A quiet, precocious romantic, and the exact opposite of Olga, Tatyana becomes intensely drawn to Onegin. Soon after, she bares her soul to Onegin in a letter professing her love. Contrary to her expectations, Onegin does not write back. When they meet in person, he rejects her advances politely but dismissively and condescendingly. This famous speech is often referred to as Onegin's Sermon: he admits that the letter was touching, but says that he would quickly grow bored with marriage and can only offer Tatyana friendship; he coldly advises more emotional control in the future, lest another man take advantage of her innocence.

Later, Lensky mischievously invites Onegin to Tatyana's name day celebration, promising a small gathering with just Tatyana, Olga, and their parents. When Onegin arrives, he finds instead a boisterous country ball, a rural parody of and contrast to the society balls of St. Petersburg of which he has grown tired. Onegin is irritated with the guests who gossip about him and Tatyana, and with Lensky for persuading him to come. He decides to avenge himself by dancing and flirting with Olga. Olga is insensitive to her fiancé and apparently attracted to Onegin. Earnest and inexperienced, Lensky is wounded to the core and challenges Onegin to fight a duel; Onegin reluctantly accepts, feeling compelled by social convention. During the duel, Onegin unwillingly kills Lensky. Afterwards, he quits his country estate, traveling abroad to deaden his feelings of remorse.

Tatyana visits Onegin's mansion, where she looks through his books and his notes in the margins, and begins to question whether Onegin's character is merely a collage of different literary heroes, and if there is, in fact, no "real Onegin". Tatyana, still brokenhearted by the loss of Onegin, is persuaded by her parents to live with her aunt in Moscow to find a suitor.

Several years pass, and the scene shifts to St. Petersburg. Onegin has come to attend the most prominent balls and interact with the leaders of old Russian society. He sees the most beautiful woman, who captures the attention of all and is central to society's whirl, and he realizes that it is the same Tatyana whose love he had once spurned. Now she is married to an aged prince (a general). Upon seeing Tatyana again, he becomes obsessed with winning her affection, despite her being married. His attempts are rebuffed. He writes her several letters, but receives no reply. Eventually, Onegin manages to see Tatyana and offers her the opportunity to finally elope after they have become reacquainted. She recalls the days when they might have been happy, but concludes that that time has passed. Onegin repeats his love for her. Faltering for a moment, she admits that she still loves him, but she will not allow him to ruin her and declares her determination to remain faithful to her husband. She leaves him regretting his bitter destiny.

As with many other 19th-century novels, Onegin was written and published serially, with parts of each chapter often appearing in magazines before the first printing of each chapter. Many changes, some small and some large, were made from the first appearance to the final edition during Pushkin's lifetime. The following dates mostly come from Nabokov's study of the photographs of Pushkin's drafts that were available at the time, as well as other people's work on the subject.