Mandamus (; lit. ''we command'') is a judicial remedy in the form of an order from a court to any government, subordinate court, corporation, or public authority, to do (or forbear from doing) some specific act which that body is obliged under law to do (or refrain from doing), and which is in the nature of public duty, and in certain cases one of a statutory duty. It cannot be issued to compel an authority to do something against statutory provision. For example, it cannot be used to force a lower court to take a specific action on applications that have been made, but if the court refuses to rule one way or the other then a mandamus can be used to order the court to rule on the applications.

Mandamus may be a command to do an administrative action or not to take a particular action, and it is supplemented by legal rights. In the American legal system it must be a judicially enforceable and legally protected right before one suffering a grievance can ask for a mandamus. A person can be said to be aggrieved only when they are denied a legal right by someone who has a legal duty to do something and abstains from doing it.