Prefabrication is the practice of manufacturing the parts of an assembly in one location, ready for them to be assembled in another place.

Prefabrication was widely used for housing during the 20th century, providing a product made in factory conditions that would save time on site and, at least in theory, improve quality.

Prefabrication also sometimes occurs in ancient times. For example, the world's oldest known engineered roadway, the Sweet Track, was prefabricated in Englandin the 3800s BC.