Black Buck, also known as Big Black Buck, is a stereotype of an African American male: large, violent, and voraciously attracted to white women. It is closely related to the African American stereotypes of the black brute and the mandingo.

According to the National Museum of African American History and Culture, the stereotype originated as White Americans feared freed African American males would attempt to exact revenge for slavery against white men by raping their daughters, while Riché Richardson says it was created at the end of the 19th century to justify lynching African Americans.

The stereotype has been depicted in films to reflect negatively on African Americans such as The Birth of a Nation (1915) and to reflect positively such as Sweet Sweetback's Baadasssss Song (1971), although it has been challenged by some in the African American community as to whether these depictions are good.

An African American male stereotyped as a black buck is large, violent, and attracted to white women in a hypersexual manner; historian Donald Bogle describes these as "big, baadddd niggers".

In depicting an African American male sexually attracted to white women, Bogle writes that these women are given symbolic value, of "white pride, power, and beauty". In the stereotype, the buck's strength makes him to a white audience at once "superhuman" and inhuman.

Vanessa Corredera writes that the stereotype persists in contemporary understandings of African American men as hypersexual, as written about by bell hooks in We Real Cool: Black Men and Masculinity.

Bogle identifies the black buck as a subdivision of the Brutish Black Buck character type. The Brutish Black Buck, according to Bogle, is one of several classic African American character types in media, alongside others including the tragic mulatto and mammy. Alongside the black buck, Brutish Black Buck is divided into black brutes, with the two subgroups closely related. For Bogle, the black brutes are anonymous, animalistic and criminal African American figures who exercise black rage, unleashing destruction. His violence was understood to derive from "sexual repression." Black Bucks, by contrast, are distinguished by their sexual assertiveness and as being more individualized, including in the danger they pose. Corredera describes the black buck as a term used to emphasize the lustful character of the Black Brute, although she also characterizes them as distinct.

In an article published by the National Museum of African American History and Culture, the black buck stereotype is said to have arisen from the earlier Mandingo stereotype. This was a concept promoted by actors in the slave trade, who invoked images of strong, young black men who could be forced to submit to their owners to undertake labor. As African Americans were emancipated, fears were borne among the white population that these African American males would exact revenge against white men by having sex with their daughters. According to Riché Richardson, the stereotype originated in the late 19th century as a justification for lynching, to supplant the dominant understanding of African American males as docile figures, seen in the stereotype of Uncle Tom.