Quia Emptores is a statute passed by the Parliament of England in 1290 during the reign of Edward I that prevented tenants from alienating (transferring) their lands to others by subinfeudation, instead requiring all tenants who wished to alienate their land to do so by substitution. The statute, along with its companion statute Quo Warranto also passed in 1290, was intended to remedy land ownership disputes and consequent financial difficulties that had resulted from the decline of the traditional feudal system in England during the High Middle Ages. The name Quia Emptores derives from the first two words of the statute in its original mediaeval Latin, which can be translated as "because the buyers". Its long title is A Statute of our Lord The King, concerning the Selling and Buying of Land. It is also cited as the Statute of Westminster III, one of many English and British statutes with that title.
Prior to the passage of Quia Emptores, tenants could either subinfeudate their land to another, which would make the new tenant their vassal, or substitute it, which would sever the old tenant's ties to the land completely and substitute the new tenant for the old with regards to obligations to the immediate overlord concerned. Subinfeudation would prove problematic so was banned by the statute.