A mudbrick or mud-brick is an air-dried brick, made of a mixture of loam, mud, sand and water mixed with a binding material such as rice husks or straw. Mudbricks are known from 9000 BCE, though since 4000 BC, bricks have also been fired, to increase their strength and durability.
In warm regions with very little timber available to fuel a kiln, bricks were generally sun-dried. In some cases, brickmakers extended the life of mud bricks by putting fired bricks on top or covering them with stucco.
The 9000 BCE dwellings of Jericho, were constructed from mudbricks, affixed with mud, as would those at numerous sites across the Levant over the following millennia. Well-preserved mudbricks from a site at Tel Tsaf, in the Jordan Valley, have been dated to 5200 BCE, though there is no evidence that either site was the first to use the technology.
The South Asian inhabitants of Mehrgarh constructed and lived in mud-brick houses between 7000–3300 BC. Mud bricks were used at more than 15 reported sites attributed to the 3rd millennium BC in the ancient Indus Valley Civilization. In the Mature Harappan phase fired bricks were used.
The Mesopotamians used sun-dried bricks in their city construction;  typically these bricks were flat on the bottom and curved on the top, called plano-convex mud bricks. Some were formed in a square mould and rounded so that the middle was thicker than the ends. Some walls had a few courses of fired bricks from their bases up to the splash line to extend the life of the building.
In Ancient Egypt, workers gathered mud from the Nile river and poured it into a pit. Workers then tramped on the mud while straw was added to solidify the mold. The mudbricks were chemically suitable as fertilizer, leading to the destruction of many ancient Egyptian ruins, such as at Edfu. A well-preserved site is Amarna. Mudbrick use increased at the time of Roman influence.
In areas of Spanish influence, mud-brick construction is called adobe, and developed over time into a complete system of wall protection, flat roofing and finishes which in modern English usage is often referred to as adobe style, regardless of the construction method.
The Great Mosque of Djenné, in central Mali, is the world's largest mudbrick structure. It, like much Sahelian architecture, is built with a mudbrick called Banco, a recipe of mud and grain husks, fermented, and either formed into bricks or applied on surfaces as a plaster like paste in broad strokes. This plaster must be reapplied annually.