National identity is a person's identity or sense of belonging to one or more states or to one or more nations. It is the sense of "a nation as a cohesive whole, as represented by distinctive traditions, culture, and language". National identity may refer to the subjective feeling one shares with a group of people about a nation, regardless of one's legal citizenship status. National identity is viewed in psychological terms as "an awareness of difference", a "feeling and recognition of 'we' and 'they'". National identity also includes the general population and diaspora of multi-ethnic states and societies that have a shared sense of common identity identical to that of a nation while being made up of several component ethnic groups. Hyphenated ethnicities are an example of the confluence of multiple ethnic and national identities within a single person or entity.

As a collective phenomenon, national identity can arise as a direct result of the presence of elements from the "common points" in people's daily lives: national symbols, language, the nation's history, national consciousness, and cultural artifacts.

Under the International Law a term national identity, with respect to states, is interchangeable with the term state's identity or sovereign identity of the state. State's identity by definition in related to the Constitutional name of the state used as a legal identification in international relations and an essential element of the state's international juridical personality. Sovereign identity of the nation also represent a common denominator for identification of the national culture or cultural identity and under the International Law any external interference into the cultural identity or cultural beliefs and traditions appears to be inadmissible. Any deprivation or external modification of the cultural national identity seems to violate the basic collective human rights.

The expression of one's national identity seen in a positive light is patriotism which is characterized by national pride and positive emotion of love for one's country. The extreme expression of national identity is chauvinism, which refers to the firm belief in the country's superiority and extreme loyalty toward one's country.