A constitutional court is a high court that deals primarily with constitutional law. Its main authority is to rule on whether or not laws that are challenged are in fact unconstitutional, i.e. whether or not they conflict with constitutionally established rights and freedoms.
The list in this article is of countries that have a separate constitutional court. Many countries do not have separate constitutional courts, but instead delegate constitutional judicial authority to their supreme court. Nonetheless, such courts are sometimes also called "constitutional courts"; for example, some have called the Supreme Court of the United States "the world's oldest constitutional court" because it was the first court in the world to invalidate a law as unconstitutional (Marbury v. Madison), even though it is not a separate constitutional court. Austria established the world's first separate constitutional court, conceptualised by Hans Kelsen, in 1920 (though it was suspended, along with the constitution that created it, from 1934 to 1945); before that, only the U.S. and Australia had adopted the concept of judicial review through their supreme courts.
Countries with separate constitutional courts include: