||The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (December 2010)
An unregistered trade mark is a trademark which does not benefit from the protection afforded to trade marks through registration.
They may however benefit from protection due to other features of the law in relation to trademarks, such as protection for unregistered marks in the United Kingdom resulting from Passing off law.
In the United States, neither federal nor state registration is required to obtain rights in a trademark. An unregistered mark may still receive common law trademark rights. Those rights, for example, may extend to its area of influence—usually delineated by geography. As such, multiple parties may simultaneously use a mark throughout the country or even state. An unregistered mark may also be protected under the federal "Lanham Act" (15 USC § 1125) prohibition against commercial misrepresentation of source or origins of goods. Unregistered marks are also protectable in the United States under Lanham Act §43(a).