A Mudbrick is an unfired brick made of clay.

In warm regions with little timber available to fuel a kiln, bricks were generally sun dried. This had the result that their useful lifespan is reduced to around thirty years. Once a building collapsed, new bricks would have to be made and the new structure rebuilt on top of the rubble of the decayed old brick. This phenomenon is the primary factor behind the mounds or tells on which many ancient cities stand.

The earliest use of mudbricks was in the Near East during the Pre-pottery Neolithic B period. The Sumerians used plano-convex mudbrick. Some bricks were formed in a square mould and rounded so that the middle was thicker than the ends. Other methods such as terre piseé (also known as pisé) involved laying down clay or mud as walls directly without separating it into bricks.

Adobe is a mudbrick from the Americas.