In sociology and in voting theory, a minority is a sub-group that is outnumbered by persons who do not belong to it. Minority only makes sense in the context of a unified society or group. This can be used to refer to people of a different language, nationality, religion, culture, lifestyle or any characteristic, provided these people are accepted as part of the referent group. The term minority is unavoidably associated with the political movement called assimilation in that it assumes a unity which is somehow disrupted.

In recent decades the term minority has taken on a new meaning among the politically correct, being used to refer to a group with which they perceive to be worthy of special preferential treatment. For instance, while numerically women outnumber men in most societies, they can be said in politically correct terms to be a minority, given their claim of inferior treatment compared to men. Some find this usage to be unhelpful or inaccurate.

A majority is a sub-group that outnumbers non-members in any particular group, or, in the politically correct sense of the word, has traditionally higher social status.

In the politics of some nations, a minority is an ethnic group that is recognized as such by respective laws of their country of habitation and therefore has some rights that ethnic groups not so recognized don't have (for example, its members might have the right to education and/or communication with the government in their mother tongue).

Not every ethnic group that is a minority in number is a "minority" in the political sense of the word: some are too small or too indistinct to validate costs of providing preferences, and some are so large or historically or otherwise important that they are one of constitutive nations. As an example, see nations of Bosnia and Herzegovina. In general, most large modern governments prefer to assume the people they rule are all members of the same ethnic group rather than separate, as in the former Yugoslavia.

There are controversial issues about both declaring minorities and the of amount of their priveleges. Some claim minorities are not given enough rights while some claim minorities demand special rights amounting to preferential discrimination, perhaps even on a path to separatism or supremacism. Some hold groups normally termed "minority" and "majority" groups to actually be completely distinct racial or ethnic groups who primarily share a common government. Such questions of identity have been considered important since the European Empires of the nineteenth century ruled large swaths of africa and asia containing either many different peoples or many different minorities, depending on one's point of view.

One particularly controversial issue is positive discrimination: the idea that (either social or legal) minorities should be given more privileges than the majority. There is also the concept of reverse discrimination, where the minority is given a status seen as superior to that of the majority, such as when minority status is used to give preference for acceptance to a university, or to gain employment over an equally qualified non-minority. In the United States this is referred to as affirmative action.