Ethnocide is the extermination or destruction of ethnic identities. Bartolomé Clavero differentiates ethnocide from genocide by stating that "Genocide kills people while ethnocide kills social cultures through the killing of individual souls". According to Martin Shaw, ethnocide is a core part of physically violent genocide. Some substitute cultural genocide for ethnocide, and other argue the distinction between ethnicity and culture. Cultural genocide and ethnocide have been used in different contexts. While the terms "ethnocide" and "ethnic cleansing" are similar, the intentions of their use vary. The term "ethnic cleansing" has been criticized as a euphemism that facilitates genocide denial by minimizing atrocities. In contrast, "ethnocide" acts as a critical tool of recognition, used by marginalized groups to assert that the destruction of their culture is a crime of genocidal proportions.

Raphael Lemkin, the lawyer who coined genocide in 1943 as the union of "the Greek word genos (race, tribe) and the Latin cide (killing)", also suggested ethnocide as an alternative form representing the same concept, using the Greek ethnos (nation) in place of genos. However, the term genocide has received much wider adoption than ethnocide.

As early as 1933, the lawyer Raphael Lemkin proposed that genocide had a cultural component, a component which he called "cultural genocide." The term has since acquired rhetorical value as a phrase that is used to protest against the destruction of cultural heritage.

The drafters of the 1948 Genocide Convention considered the use of the term, but dropped it from their consideration. The legal definition of genocide is left unspecific about the exact nature in which genocide is done, only stating that it is destruction with intent to destroy a racial, religious, ethnic or national group as such.

Article 7 of a 1994 draft of the United Nations Declaration on the Rights of Indigenous Peoples uses the word "ethnocide" as well as the phrase "cultural genocide" but it does not define what they mean. The complete article reads as follows:

The United Nations Declaration on the Rights of Indigenous Peoples was adopted by the United Nations General Assembly during its 62nd session at UN Headquarters in New York City on 13 September 2007, but only mentions "genocide" in its Article 7, not "cultural genocide." Article 8 in the final document otherwise substantially retains the wording of the draft Article 7, but its first sentence reads "indigenous peoples and individuals have the right not to be subjected to forced assimilation or destruction of their culture".

In UNESCO's "Declaration of San Jose":

The Declaration of San Jose commits the United States and the nations of Central America to engage in a more in-depth discussion about a broad range of issues. These issues include: strengthening democracy and regional security, building trade and investment, combating crime, drugs and corruption, promoting dialogue on immigration, and achieving more equitable and sustainable development. In the Declaration of San José, UNESCO also addresses and works to define ethnocide. UNESCO defines the term as follows: