A government is a body that has the authority to make and the power to enforce rules and laws within a civil, corporate, religious, academic, or other organization or group. In its broadest sense, "to govern" means to administer or supervise, whether over a state, a set group of people, or a collection of assets.

Typically, "the government" refers to the executive function of the state. In many countries (particularly those having parliamentary systems), the government refers to the executive branch of government or a specifically named executive, such as the Blair government (compare to the administration as in the Bush administration in U.S. usage). In countries using the Westminster system, the party in government will also usually control the legislature.

One of the most influential theories of government in the past two hundred years has been the social contract, on which modern democracy and most forms of socialism are founded. The social contract theory holds that governments are created by the people in order to provide for collective needs (such as safety from crime, poverty, illiteracy) that cannot be properly satisfied using purely individual means. Governments thus exist for the purpose of serving the needs and wishes of the people, and their relationship with the people is clearly stipulated in a "social contract" (a constitution and a set of laws) which both the government and the people must abide by. If a majority is unhappy, it may change the social contract. If a minority is unhappy, it may persuade the majority to change the contract, or it may opt out of it by emigration or secession. This theory is based on the idea that all men live in a state of nature which is not ideal to perfect harmony. It is also an agreement among the members of an organized society or between the governed and the government defining and limiting the rights and duties of each. Today, natural rights are the basis for many issues involving the constitution and ones right to privacy under the government.