Nigga (/ˈnɪɡə/ ^ⓘ), also known as "the N-word", is a colloquial term in African-American Vernacular English that is considered as a vulgar word in most contexts of its use. It began as a dialect form of the word nigger, an ethnic slur against black people. As a result of reappropriation, today the word is used mostly by African-Americans in a largely non-pejorative sense as a slang term referring to another person or to themselves, often in a neutral or friendly way. The word is commonly associated with hip hop culture and since the 1990s, with gangs (especially in popular culture). The word is more often applied to men, with more select terms being used for women in the culture.

In dialects of English that have non-rhotic speech (including standard British English), the hard-r nigger and nigga are usually pronounced the same.

The use of nigger non-pejoratively within the black community was documented in the 1912 novel The Autobiography of an Ex-Colored Man by African-American writer James Weldon Johnson, in which he recounted a scene in New York City around the turn of the century:

I noticed that among this class of colored men the word "nigger" was freely used in about the same sense as the word "fellow," and sometimes as a term of almost endearment; but I soon learned that its use was positively and absolutely prohibited to white men.

There is conflicting popular opinion on whether there is any meaningful difference between nigga and nigger as a spoken term. Many people consider the terms to be equally pejorative, and the use of nigga both in and outside black communities remains controversial. H. Lewis Smith, author of Bury That Sucka: A Scandalous Love Affair with the N-word, believes that "replacing the 'er' with an 'a' changes nothing other than the pronunciation" and the African American Registry notes, "Brother (Brotha) and Sister (Sistah or Sista) are terms of endearment. Nigger was and still is a word of disrespect." The National Association for the Advancement of Colored People, a civil rights group, condemns the use of both nigga and nigger.

Many African-Americans consider nigga only offensive when used by people of another other race, with some seeing its use outside a defined social group as an unwelcome cultural appropriation. Used by black people, the term may indicate "solidarity or affection", similar to the usage of the words dude, homeboy, and bro. Some consider nigga non-offensive except when directed from a non-African-American towards an African-American. Yet others have derided this as hypocritical and harmful, enabling white racists to use the word and confusing the issue over nigger. Conversely, nigga has been used an example of cultural assimilation, whereby some members of other ethnicities (particularly younger people) will use the word in a positive way, similar to the previously mentioned dude, homeboy, and bro, although this usage remains very controversial. Members of other ethnicities will not use the word while around African-Americans, especially those they do not know.

In practice, its use and meaning are heavily dependent on context, with non-offensive examples ranging from a greeting, to reprimand, to general reference, to a use synonymous with male person.^{[citation needed]} As of 2007^[update], the word nigga was used more liberally by some younger members of all races and ethnicities in the United States. In addition to African-Americans, other ethnic groups have adopted the term as part of their vernacular, although this usage is very controversial.

The phrase nigga, please, used in the 1970s by comics such as Paul Mooney as "a funny punctuation in jokes about Blacks", is now heard routinely in comedy routines by African-Americans. The growing use of the term is often attributed to its ubiquity in modern American hip hop music.