Ownership is the state or fact of exclusive possession or control of property, which may be an object, land/real estate, intellectual property or some other kind of property.

Ownership is the key building block in the development of the capitalist socio-economic system. The concept of ownership has existed for thousands of years and in nearly all cultures. Over the millennia, however, and across cultures what is considered eligible to be property and how that property is regarded culturally is very different. Ownership is the basis for many other concepts that form the foundations of ancient and modern societies such as money, trade, debt, bankruptcy, the criminality of theft and private vs. public property.

The process and mechanics of ownership are fairly complex since one can gain, transfer and lose ownership of property in a number of ways. To acquire property one can purchase it with money, trade it for other property, receive it as a gift, steal it, find it, make it or homestead it. One can transfer or lose ownership of property by selling it for money, exchanging it for other property, giving it as a gift, being robbed of it, misplacing it, or having it stripped from one's ownership through legal means such as eviction, foreclosure and seizure. Ownership is self-propagating in that if an object is owned by someone, any additional goods produced by using that object will also be owned by the same person. If one finds an object, one can legitimately take ownership of that object as long as no one claims to have previously lost that object. Some jurisdictions place time restraints on finding lost property before that property becomes fair game for anyone to claim ownership of once found. Such is the case of the gold found in the sunken SS Republic. The SS Republic steamship sank off the coast of Georgia in 1865 and lost thousands of gold coins and bars to the ocean. In 2003 Odyssey Marine Exploration, Inc. discovered the ship and was awarded possession of the gold after the insurance company that had paid off damages to the original owners claimed they were the rightful owners of the gold.