A parliamentary republic or parliamentary constitutional republic is a form of a republic which operates under a parliamentary system of government.

In contrast to a presidential republic and the semi-presidential system, the head of state usually does not have broad executive powers as an executive president would, because much of those powers have been granted to a "head of government" (usually called a prime minister). However, the head of government and head of state may form one office in a parliamentary republic (such as South Africa and Botswana), but the president is still elected in much the same way as the prime minister is in most Westminster systems. This usually means that they are the leader of the largest party or coalition of parties in parliament.

In some instances, the President may legally have executive powers granted to them to undertake the day-to-day running of government (as in Finland) but by convention they do not use these powers. Some parliamentary republics could therefore be seen as following the semi-presidential system but operating under a parliamentary system.