A barn raising, also historically called a raising bee or rearing in the U.K., is a collective action of a community, in which a barn for one of the members is built or rebuilt collectively by members of the community. Barn raising was particularly common in 18th- and 19th-century rural North America. A barn was a necessary structure for any farmer, for example for storage of cereals and hay and keeping of animals. Yet a barn was also a large and costly structure, the assembly of which required more labor than a typical family could provide. Barn raising addressed the need by enlisting members of the community, unpaid, to assist in the building of their neighbors' barns. Because each member could ask others for help, reciprocation could eventually reasonably be presumed for each participant if the need were to arise.

The tradition of "barn raising" continues, more or less unchanged, in some Amish and Old Order Mennonite communities, particularly in Ohio, Indiana, Pennsylvania, and some rural parts of Canada. The practice continues outside of these religious communities, albeit less frequently than in the 19th century. Most frames today are raised using a crane and small crew.