Cosette (French pronunciation: [kɔzɛt]) is a fictional character in the 1862 novel Les Misérables by Victor Hugo and in the many adaptations of the story for stage, film, and television.

Valjean's struggle to protect her while disguising his past drives much of the plot until he recognizes "that this child had a right to know life before renouncing it"[1]—and he must allow her romantic attachment to Marius to blossom.

Tholomyès abandons Fantine, who leaves three-year-old Cosette with the Thénardiers at their inn in Montfermeil, paying them to care for her child while she works in the city of Montreuil-sur-Mer.

Under the Thénardiers' care she is described as "thin and pale", wears rags for clothing, and has chilblains on her hands as well as bruised and reddened skin.

While Fantine is in the hospital, the mayor of Montreuil-sur-Mer—Jean Valjean masquerading as "Madeleine" to avoid revealing that he is a paroled convict—vows to retrieve Cosette for her.

When he arrives in Montfermeil on Christmas Eve, Valjean finds Cosette fetching a pail of water and accompanies her back to the inn, where he witnesses her mistreatment by the Thénardiers as well as the unkindnesses of their daughters Éponine and Azelma.

In a later chapter, Cosette eventually remembers her childhood—praying for the mother she never knew; the two ugly Thénardiers, and fetching them water somewhere "very far from Paris".

When he learns that Marius has followed them home and inquired about them, he quickly moves to a more obscure address with Cosette.

When Cosette and Marius finally meet again in the garden, they confess their mutual love, share their first kiss, and introduce themselves.

Their discussion dissolves into a heated argument stemming from the grandfather's suggestion to "Make her [his] mistress", and Marius storms out.

The next day, Éponine (now dressed as a boy) finds Valjean in an embankment in the Champ de Mars and anonymously throws him a note, which tells him to "move".

Valjean considers this in horror for a few days, then informs Cosette they will move to their other house and will be in England in a week.

Critics have often considered Cosette to be something of an empty figure, with no real independent character apart from the role she plays in the lives of others: as an innocent, hopeless child-victim to be exploited (for the Thénardiers); a daughter to be protected (for Fantine and Valjean); and an object of adoration (for Marius).

Stephanie Barbé Hammer writes that "Having served her function as a paternalizing figure, Cosette grows up into a silent, beautiful cipher".

Before the wedding the young people exchange one kiss, which is not repeated because, as the narrator says, neither Marius nor Cosette was aware of the existence of carnal desire....

For this reason the picture of her sweeping the inn in the evening is often the image most associated as being singularly representative of the main themes of the book, and is used frequently on the cover.

Since the original publication of Les Misérables in 1862, the character of Cosette has been included in many adaptations in various media, including books, films,[8] musicals, plays and games, most notably in the 2007 anime Les Misérables: Shōjo Cosette, in which she rather than Valjean is the central character.

Her role as an adolescent is condensed while her joy in singing and reading is only implied (specifically in "Castle on the Cloud").

Many other details of her character including her passionate nature ("A Heart Full of Love") are similarly portrayed by implication in the songs she sings.

Other aspects were fully omitted including the conversation between Valjean and Cosette as he helps her carry the water bucket, their stay at Gorbeau House, their avoidance of Javert and their arrival at the Petit-Picpus convent, much of which were later reintroduced in the 2012 film adaptation.