A Parliamentary System is a system of government in which the ministers of the Executive Branch get their legitimacy from a Legislature and are accountable to that body, such that the Executive and Legislative branches are intertwined.

A Parliamentary System may consist of two styles of chambers of parliament one with two chambers (or houses): an elected lower house, and an upper house or Senate which may be appointed or elected by a different mechanism from the lower house. This style of two houses is called bicameral system. Legislatures with only one house are known as unicameral system. Scholars of Democracy such as Arend Lijphart divide Parliamentary Democracies into two different systems, the Westminster and Consensus systems.

Implementations of the parliamentary system can also differ on whether the government needs the explicit approval of the parliament to form, rather than just the absence of its disapproval, and under what conditions (if any) the government has the right to dissolve the parliament, like Jamaica and many others.^{[citation needed]}