A cartoon is a type of visual art that is typically drawn, frequently animated, in an unrealistic or semi-realistic style. The specific meaning has evolved, but the modern usage usually refers to either: an image or series of images intended for satire, caricature, or humor; or a motion picture that relies on a sequence of illustrations for its animation. Someone who creates cartoons in the first sense is called a cartoonist, and in the second sense they are usually called an animator.

The concept originated in the Middle Ages, and first described a preparatory drawing for a piece of art, such as a painting, fresco, tapestry, or stained glass window. In the 19th century, beginning in Punch magazine in 1843, cartoon came to refer – ironically at first – to humorous artworks in magazines and newspapers. Then it also was used for political cartoons and comic strips. When the medium developed, in the early 20th century, it began to refer to animated films that resembled print cartoons.

In fine art, a cartoon (from Italian: cartone and Dutch: karton—words describing strong, heavy paper or pasteboard and cognates for carton) is a full-size drawing made on sturdy paper as a design or modello for a painting, stained glass, or tapestry. Cartoons were typically used in the production of frescoes, to accurately link the component parts of the composition when painted on damp plaster over a series of days (giornate). In media such as stained tapestry or stained glass, the cartoon was handed over by the artist to the skilled craftsmen who produced the final work.

Such cartoons often have pinpricks along the outlines of the design so that a bag of soot patted or "pounced" over a cartoon, held against the wall, would leave black dots on the plaster ("pouncing"). Cartoons by painters, such as the Raphael Cartoons in London, Francisco Goya's tapestry cartoons, and examples by Leonardo da Vinci, are highly prized in their own right. Tapestry cartoons, usually colored, could be placed behind the loom, where the weaver would replicate the design. As tapestries are worked from behind, a mirror could be placed behind the loom to allow the weaver to see their work; in such cases the cartoon was placed behind the weaver.

In print media, a cartoon is a drawing or series of drawings, usually humorous in intent. This usage dates from 1843, when Punch magazine applied the term to satirical drawings in its pages, particularly sketches by John Leech. The first of these parodied the preparatory cartoons for grand historical frescoes in the then-new Palace of Westminster in London.

Sir John Tenniel—illustrator of Alice's Adventures in Wonderland—joined Punch in 1850, and over 50 years contributed over two thousand cartoons.

Cartoons can be divided into gag cartoons, which include editorial cartoons, and comic strips.

Modern single-panel gag cartoons, found in magazines, generally consist of a single drawing with a typeset caption positioned beneath, or, less often, a speech balloon. Newspaper syndicates have also distributed single-panel gag cartoons by Mel Calman, Bill Holman, Gary Larson, George Lichty, Fred Neher and others. Many consider New Yorker cartoonist Peter Arno the father of the modern gag cartoon (as did Arno himself). The roster of magazine gag cartoonists includes Charles Addams, Charles Barsotti, and Chon Day.