Casting is a manufacturing process by which a liquid material is (usually) poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solid casting is then ejected or broken out to complete the process. Casting may be used to form hot liquid metals or various materials that cold set after mixing of components (such as epoxies, concrete, plaster and clay).

Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. The oldest surviving casting is a copper frog from 3200 BC. The casting process is subdivided into two distinct subgroups: expendable and non-expendable mold casting.