Honoré-Victorin Daumier (French: [ɔnɔʁe domje]; 26 February 1808 – 10 or 11 February 1879) was a French painter, sculptor, and printmaker, whose many works offer commentary on the social and political life in France, from the Revolution of 1830 to the fall of the Second French Empire in 1870. He earned a living producing caricatures and cartoons in newspapers and periodicals such as La Caricature and Le Charivari, for which he became well known in his lifetime and is still remembered today. He was a republican democrat (working class liberal), who satirized and lampooned the monarchy, aristocracy, clergy, politicians, the judiciary, lawyers, police, detectives, the wealthy, the military, the bourgeoisie, as well as his countrymen and human nature in general.

Daumier was a serious painter, loosely associated with realism, sometimes blurring the boundaries between caricature and fine art. Although he occasionally exhibited at the Parisian Salon, his paintings were largely overlooked and ignored by the French public and critics of the day. Yet Daumier's fellow painters, as well as the poet and art critic Charles Baudelaire, noticed and greatly admired his work. Later generations would recognize Daumier as one of the great French artists of the 19th century, profoundly influencing a younger generation of impressionist and postimpressionist painters. Daumier was a tireless and prolific artist and produced more than 100 sculptures, 500 paintings, 1,000 drawings, 1,000 wood engravings, and 4,000 lithographs.

Daumier came from a poor family and was working by the age of 12, first at a huissier de justice, then at a bookstore frequented by artists where he began to draw. He received some mentorship from Alexandre Lenoir, attended the Académie Suisse, learned lithography, and was producing advertisements, illustrations, and caricatures by the time he was twenty. After the July Revolution of 1830 he begin working for satirical political papers that were highly critical of the new monarch Louis Philippe I and his court. He was jailed for several months in 1832 after the publication of Gargantua, a particularly offensive depiction of the King, Louis Philippe. After his release Daumier resumed publishing political lithographs until the September Laws were passed in 1835, limiting the freedom of the press. Afterwards, his cartoons softened, the bourgeoisie and daily Parisian life were more frequent subjects, and when political subjects did appear they were oblique and veiled. Daumier experienced financial hardships and debt throughout much of his life.

Daumier married Alexandrine Dassy in 1846 and moved to the Île Saint-Louis where they lived until 1863. He increasingly associated with writers, poets, painters, and sculptors there, including Baudelaire, Corot, Courbet, Delacroix among others, and began to paint in earnest. He spent his summers from 1853 onward in Barbizon and Valmondois, where artists of the Barbizon school and realist movement worked. As his desire to paint intensified, his enthusiasm for cartooning declined, as did his popularity with the public. Le Charivari stopped publishing his comics in 1860. A period of financial hardship followed, and from 1863–1865 he moved to a series of lodgings around Montmartre and lost contact with many friends. Le Charivari gave him a new contract in 1864 and he resumed making caricatures for an appreciative audience in Paris. Daumier moved to Valmondois in 1865. He experienced failing eyesight and poverty there, although he continued to produce lithographs and paint, often on the theme of Don Quixote. The French Third Republic granted him a pension in 1877, and the following year a major exhibition of his paintings was held in Paris, which received significant recognition in the final months of his life. Daumier died in February 1879. Various sources give conflicting dates regarding the day of his death: some state 10 February 1879, others 11 February.

Daumier was born in the south of France, in Marseille, to Jean-Baptiste Louis Daumier and Cécile Catherine Philippe. His father Jean-Baptiste was a glazier (corresponding nowadays to a framer), a poet and a minor playwright whose literary aspirations led him to move to Paris in 1814, followed by his wife and the young Daumier in 1816. Although Daumier's father succeeded in publishing a book of verse and having an amateur troupe of actors perform his play in 1819, financial success was minimal and the family lived in poverty. At about the age of twelve (c. 1820–21), Daumier started to work because of his father's breakdown. His father found him a job working as an errand boy for a huissier de justice. Later he found employment at Delaunay's, a well established bookstore at the Palais-Royal, a hub of Parisian life, where he began to meet artists, develop an interest in art, and started drawing. He spent much of his free time in the Louvre. In 1822 he became protégé to Alexandre Lenoir, a friend of Daumier's father and the founder of the Musée des Monuments Francais (now Musée national des Monuments Français), who trained Daumier in the fundamentals of art. The following year he entered the Académie Suisse where he was able to draw from live models and develop friendships with other students including Philippe Auguste Jeanron and Auguste Raffet.

Lithography was a relatively new form of printmaking in the early 19th century, invented in Germany in the late 1790s. It was a fast and cheap method of mass-producing prints compared to the traditional practices of engraving and etching. Likewise, the art of the caricature, which was relatively established and popular in England (e.g. William Hogarth, Thomas Rowlandson), was just coming into vogue in France about this time. Lithography studios were emerging in Paris to fill demands for inexpensive illustrated papers and periodicals in a time of social and political upheaval. Daumier learned lithography from Charles Ramelet (1805–1851) and found work with Zéphirin Belliard (1798–1861), producing (often anonymously), miscellaneous illustrations, advertisements, street scenes, portraits, and caricatures in the mid to late 1820s, albeit honing his craft through the years.

After the "Three Glorious Days" of the July Revolution of 1830 (it is unknown if Daumier participated in actual street fighting), a number of new illustrated satirical journals emerged in Paris. These were left-wing publications, intended for the working classes. They were largely driven by the idea that the 1830 Revolution which brought Louis Philippe I to power, was largely fought and won by the workers, but had been commandeered by the ruling class and bourgeoisie for their own gains and benefits, who in turn were favored by the king. Daumier's first works of note appeared in La Silhouette, the first illustrated weekly satirical paper in France which ran from December 1829 to 2 January 1831. Daumier eagerly threw in his support and began to express his political convictions as a working class republican in opposition to the new monarchy, its bureaucracy, and the bourgeoisie that supported and profited from it. The editors of La Silhouette were prosecuted and jailed for a time during the short run of the paper. Charles Philipon and Gabriel Aubert, founded another satirical paper, La Caricature in 1830, starting up just as La Silhouette was folding under pressure from the monarchy. La Caricature invited Daumier to join its staff, a formidable group including Achille Devéria, Jean Ignace Isidore Gérard (J. J. Grandville), Auguste Raffet. and a young Honoré de Balzac as a literary editor, who is reported to have said of Daumier's lithographs "Why, this fellow's got Michelangelo in his blood !"

Daumier's caricature of King Louis Philippe I, titled Gargantua, was published in December 1831. He was brought to court in February 1832 and charged with "inciting to hatred and contempt of the government and insulting the king" and sentenced to six months imprisonment with a fine of 500 francs. However, his sentence was suspended at that time and Daumier returned to work where he continued to produce provocative and antagonistic lithographs for the papers. It was at this time he started work on his first sculptures, the Célébrités du Juste Milieu (1832–1835). Later that year, his cartoon The Court of King Pétaud (1832) was published and he was arrested at his parents apartment in August 1832 and placed in the prison of Sainte-Pélagie to serve his six months. Daumier remained defiant in prison and wrote a number of letters indicating that he was producing lots of drawings "just to annoy the government." The publication of Gargantua and his imprisonment brought Daumier considerable notoriety, and great popularity among some segments of the public, but little financial gain.