Multiple citizenship, also called dual citizenship or multiple nationality, is a person’s citizenship status, in which a person is concurrently regarded as a citizen of more than one state under the laws of those states. There is no international convention which determines the nationality or citizen status of a person, which is defined exclusively by national laws, which vary and can be inconsistent with each other. Multiple citizenship arises because different countries use different, and not necessarily mutually exclusive, criteria for citizenship. Colloquial speech refers to people “holding” multiple citizenship but technically each nation makes a claim that this person be considered its national.
Some countries do not permit dual citizenship. This may be by requiring an applicant for naturalisation to renounce all existing citizenships, or by withdrawing its citizenship from someone who voluntarily acquires another citizenship, or by other devices. Some permit a general dual citizenship while others permit dual citizenship but only of a limited number of countries.

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