Mural painting, one of the oldest forms of artistic expression, includes all painting executed for the express purpose of embellishing or decorating a wall. The word mural is derived from the Latin murus ("wall"). A variety of techniques can be subsumed under the general heading of mural painting. The term fresco (sometimes incorrectly used interchangeably with mural, refers to only one technique of mural painting. In true fresco, or buon fresco, pigment is applied to wet plaster, so that the paint actually becomes part of the wall. In fresco secco, or dry fresco, the artist applies pigment to a specially prepared wall whose surface has first been allowed to dry. Other techniques of mural painting include encaustic; painting on canvas which is then affixed to a wall; painting in various pigments directly on the surface of the wall; scratching designs into a wall; mosaic; stained glass; baked enamel; modern synthetic materials; and photographic murals.

The earliest evidence (14,000-10,000 BC) of mural art is provided by the cave paintings discovered at Altamira, Spain (1879) and Lascaux, France (1940), in which animals are depicted in yellow, red, black, and brown earth-pigments. Another form of prehistoric mural, called rock art, consists of incised designs on exposed rocks or rock shelters. Beginning in the 3d millennium BC, Egyptian artists decorated the walls of tombs with formal scenes of warfare, hunting, and ceremonies. Fresco was first used (circa 1700 BC) in the lively work of the Minoan art of Crete, although little remains of these early efforts. Largely vanished also are the epic murals of classical Greece (6th-5th centuries BC), to which Greek literature often refers. Most direct knowledge of Greek wall painting comes from the sophisticated and action-filled mosaics of the Hellenistic Period, of which the Olynthos mosaics (circa 400 BC) are the prime example. Roman artists adopted and developed the art of mosaic, and they filled the walls of homes and temples with naturalistic wall paintings such as those preserved at Pompeii and Herculaneum. Pompeiian paintings reflect the great range and expertise of classical muralists, who were adept at depicting illusionistic architectural settings and realistic landscape, animals, and portraits.