Caveat emptor (; from caveat, "may he/she beware", a subjunctive form of cavēre, "to beware" + ēmptor, "buyer") is Latin for "Let the buyer beware". It has become a proverb in English. Generally, caveat emptor is the contract law principle that controls the sale of real property after the date of closing, but may also apply to sales of other goods. The phrase caveat emptor and its use as a disclaimer of warranties arises from the fact that buyers typically have less information than the seller about the good or service they are purchasing. This quality of the situation is known as 'information asymmetry'. Defects in the good or service may be hidden from the buyer, and only known to the seller.

It is a short form of Caveat emptor, quia ignorare non debuit quod jus alienum emit ("Let a purchaser beware, for he ought not to be ignorant of the nature of the property which he is buying from another party.") I.e. the buyer should assure himself that the product is good and that the seller had the right to sell it, as opposed to receiving stolen property.

A common way that information asymmetry between seller and buyer has been addressed is through a legally binding warranty, such as a guarantee of satisfaction.