A form of government is a system by which a state is governed. A wide range of different forms of government have been suggested and/or used in practice. The following is a list of common forms of government. Note that in practice, it is possible to combine multiple simple forms in a government. The theory and study of comparison and combination of such forms is called civics.

These forms of government give a general schematic of the power structure contained within the government of a country. However, every government is unique and so is every country and its constitution - the basic law which describes the form of government for the state in detail.

Such basic outlines are insufficient descriptions for the continued function of any government. As such, political authorities often distribute and structure power and responsibility to a greater extent than the form of government dictates. A representative democracy for instance such as those of Canada and the United States includes measures for a degree of direct democracy in the form of a referendum, for deliberative democracy in the form of the elaborate process they undergo for constitutional change, and investigating committees and commissions (not always led by representatives), and bioregional democracy in the form of co-ordinating bodies governing ecoregions and watersheds they share, e.g. the Great Lakes.

Socialism, Communism and Fascism originated as socio-economic movements and were carried into governments by specific parties naming themselves after those movements. Long experience with those movements in power, and the strong ties of each ideology to governmental control and policy have won them some recognition as forms of government in themselves. Bioregional democracy is likewise basic to green politics.

Islam as a political movement is also often included on a list of movements that have deep implications for the form of government, but are in practice so differently applied that it makes little sense to treat them as one of the more abstractly defined movements above. Many nations in the Islamic World call themselves Islamic, often that term is in the name of the state, but in practice, these governments just as often exploit mechanisms of power (such as debt and appeals to nationalism) that have no roots, and sometimes much opposition, in Islam as a religion and as a political practice.