A courthouse is a government building housing courtrooms and judicial chambers. Depending on the country's legal system it may also contain jury rooms and many other supporting functions. Courthouses are very often designated at a particular level within the judicial system; for example there are federal and sub-national courts, appellate courts, and supreme courts. Some courthouses are specialized to hear certain types of cases (traffic courts, divorce courts, criminal courts, civil courts, etc.).

Judicial proceedings and the chambers supporting them define the building's purpose. Jury rooms can be present where the legal system uses juries; their absence does not by itself exclude a courthouse.

The court can be distinguished by territorial jurisdiction or by the kind of cases it hears. A prosecutor's office accommodates case preparation outside court, while a prison accommodates incarceration under a sentence; neither function alone establishes a courthouse.