Thérèse Raquin (French pronunciation: [teʁɛz ʁakɛ̃]) is an early novel by French writer Émile Zola. The germ of the novel was present in his short story "Un Mariage d'Amour", published in December 1866. He then expanded the story into a novel, which appeared in serial form from August–October 1867 in the magazine L'Artiste. Later that year it was published in book form. Although it was Zola's third novel, Thérèse Raquin was the one that earned him fame and notoriety. The plot, with its focus on adultery and murder, was considered scandalous and described as "putrid literature" in a review in Le Figaro.

The novel tells the tale of a young woman, Thérèse Raquin, who is coerced by an overbearing aunt into a loveless marriage with her first cousin Camille. He is sickly and egocentric and when the opportunity arises, Thérèse enters into a turbulent, sordid affair with Camille's friend, Laurent. Despite their numerous trysts, Thérèse and Laurent are convinced they can only be truly happy if they are married. To do that, they must kill Camille, and so they carry out the murderous deed. The plan works – they wed two years after his death – but they are so haunted by guilt they begin to hate each other.

In Zola's preface to the second edition, published in 1868, he explained that his goal was "to study, not characters, but temperaments". Because of its detached, scientific approach, the novel is considered a seminal work in the movement known as literary naturalism. Zola adapted Thérèse Raquin for the stage in 1873. It has since been adapted for other media including opera, musical theater, film, radio and television.

Thérèse Raquin is the daughter of a French sea captain and Algerian mother. After her mother's early death, Thérèse is placed in the countryside with her aunt, Madame Raquin, and her aunt's valetudinarian son Camille. Because he is "ill", Madame Raquin dotes on him to the point of spoiling him, and he grows up self-centered. Thérèse and Camille are raised side-by-side. When Thérèse turns 21, Madame Raquin persuades the cousins to marry each other, though neither feels any love regarding the match. Shortly thereafter, Camille insists that the family must move to Paris so that he can find a profession.

To support him in Paris while he seeks employment, Madame Raquin and Thérèse set up a haberdashery shop in the Passage du Pont Neuf. Camille obtains an office job where he encounters Laurent, a childhood friend and amateur painter. Laurent visits the Raquins and, while painting a portrait of Camille, decides to seduce the lonely Thérèse, mostly because he cannot afford prostitutes anymore. It soon becomes a torrid affair. They have frequent late-afternoon rendezvous in Thérèse's room. But when Laurent's boss no longer allows him to leave work early, the lovers must think of some other means to be together. Since they are infatuated with the dream of living openly as a married couple, Thérèse suggests killing Camille: he is the obstacle to achieving their dream.

Laurent lures Camille, who cannot swim, into taking a boating trip along with Thérèse. At a secluded spot on the river, Laurent chokes Camille and attempts to throw him off the boat. While defending himself, Camille bites Laurent on the neck. Eventually, Laurent overpowers Camille and drowns him. Laurent goes to the authorities and says his friend is missing and may have fallen overboard. Laurent and Thérèse deliver the devastating news to Madame Raquin that her son has disappeared. Everyone believes it was a boating accident and that the two of them tried valiantly to save Camille. The body is not discovered for days. Laurent is uncertain about whether Camille is actually dead. Laurent often visits the mortuary, even though it disturbs him, until he finds Camille's corpse there. Thérèse becomes nervous and has nightmares; the previously calm and centered Laurent also grows agitated. Their feelings toward each other change. They do not renew their affair, but still devise a plan to marry, without raising suspicion, and thereby reap the rewards of their crime.

The widowed Thérèse acts depressed around family and acquaintances, and Laurent publicly shows concern for her mental state. Michaud advises that Thérèse should remarry to revive her spirits, and that the ideal husband would be Laurent. The two finally marry but are haunted by the memory of the murder; Laurent's bite scar serves as a reminder. They have hallucinations of the dead Camille visiting their bedroom at night. They vacillate between trying to rekindle their passion to rid themselves of disturbing visions (and maybe "heal" the bite scar), and at the same time starting to despise one another. Laurent resumes painting, but every picture he draws resembles the dead man. Sickened by this, Laurent gives up art. He and Thérèse must also tend to Madame Raquin, who suffered a stroke after Camille's death. She has a second stroke and becomes paralyzed and mute.

During a heated argument, Thérèse and Laurent reveal in Madame Raquin's presence that they murdered Camille. She had believed they loved her son and mourned his passing, but now she is filled with rage, disgust, and horror. While friends are visiting for an evening game of dominoes, she manages with extreme effort to move her finger in a writing motion on the table. She traces out the words "Thérèse et Laurent ont ...". The complete sentence was meant to be "Thérèse et Laurent ont tué Camille" (Thérèse and Laurent killed Camille), but her strength gives out before she can finish. The clueless Michaud interprets her intended message as, "Thérèse and Laurent look after me very well."