Squatting is the action of occupying an abandoned or unoccupied area of land or a building, usually residential, that the squatter does not own, rent or otherwise have lawful permission to use. The United Nations estimated in 2003 that there were one billion slum residents and squatters globally. Squatting occurs worldwide and tends to occur when people find empty buildings or land to occupy for housing. It has a long history, broken down by country below.

In common law systems, land tenure, from the French verb "tenir" means "to hold", is the legal regime in which land "owned" by an individual is possessed by someone else who is said to "hold" the land, based on an agreement between both individuals. It determines who can use land, for how long and under what conditions. Tenure may be based both on official laws and policies, and on informal local customs. In other words, land tenure implies a system according to which land is held by an individual or the actual tiller of the land but this person does not have legal ownership. It determines the holder's rights and responsibilities in connection with their holding. The sovereign monarch, known in England as the Crown, held land in its own right. All land holders are either its tenants or sub-tenants. Tenure signifies a legal relationship between tenant and lord, arranging the duties and rights of tenant and lord in relationship to the land. Over history, many different forms of land tenure, i.e., ways of holding land, have been established.