In English common law, real property, real estate, immovable property or realty, refers to parcels of land and any associated structures which are the property of a person. For a structure (also called an improvement or fixture) to be considered part of the real property, it must be integrated with or affixed to the land. This includes crops, buildings, machinery, wells, dams, ponds, mines, canals, and roads. The term is historic, arising from the now-discontinued form of action, which distinguished between real property disputes and personal property disputes. Personal property, or personalty, was, and continues to be, all property that is not real property.

In countries with personal ownership of real property, civil law protects the status of real property in real-estate markets, where estate agents work in the market of buying and selling real estate. Scottish civil law calls real property heritable property, and in French-based law, it is called immobilier ("immovable property").

The word "real" derives from Latin res ("thing"). Under European civil law, a lawsuit that seeks official recognition of a property right is known as an actio in rem (action in relation to a thing). This contrasts with an actio in personam in which the plaintiff seeks relief for the actions of a particular person. The distinction can be subtle; the medieval action of novel disseisin, although aimed at repossessing land, was not an actio in rem because it claimed dispossession without leave rather than rightful possession.

Henry de Bracton's Treatise on the Laws and Customs of England is credited with giving "real property" its particular meaning in English law. After discussing the distinction in civil law, Bracton proposed that actions for movable property were inherently actions for relief, and that therefore an actio in rem could be brought only upon immovable property. This view is not accepted in continental civil law, but can be understood in the context of legal developments during Bracton's lifetime. In thirteenth-century England the courts of canon law claimed broad authority to interpret wills, but inheritance of land remained a matter for the royal courts. Laws governing the conveyance of land and that of movable personal property then developed along different paths.

In modern legal systems derived from English common law, the classification of property as real or personal may vary somewhat according to jurisdiction or, even within jurisdictions, according to purpose, as in defining whether and how the property may be taxed. Houseboats, for example, occupy a grey area between personal and real property, and may be treated as either according to jurisdiction or circumstance. Bethell (1998) contains much information on the historical evolution of real property and property rights.

Real property is immobile. Owners cannot move their land to a better location, such as another city, for sale. Thus the fixed location of a parcel of land directly affects, and is a major determinant of, its value.

However, products of the land, such as minerals and crops, can be transported.

Changes that take place nearby will directly affect the real property's value. Real property is vulnerable to externalities due to its immobile nature. External factors outside of the real property will affect the value of the real property, for example, the noises that neighbouring people and construction sites produce.