A congressional system is a form of government that features a powerful, lawmaking congress as one of its main organs.

A congressional government is different from a parliamentary government as it does not have a Prime Minister. The congress may have a nominal head, but usually the powers of Head of State and Head of Government rest with a president who is not a member of the legislative branch. For this reason, the term congressional system is often used interchangeably with presidential system.

The other key difference is a congressional government rarely uses the principle of the vote of no confidence, and as a result tends to have very weak party discipline.

Nations with congressional governments are the United States, Mexico, Switzerland, and most nations in South America.

See also: republic