Separate but equal was a legal doctrine in United States constitutional law, according to which racial segregation did not necessarily violate the Fourteenth Amendment to the United States Constitution, which nominally guaranteed "equal protection" under the law to all people. Under the doctrine, as long as the facilities provided to each race were equal, state and local governments could require that services, facilities, public accommodations, housing, medical care, education, employment, and transportation be segregated by race, which was already the case throughout the states of the former Confederacy. The phrase was derived from a Louisiana law of 1890, although the law actually used the phrase "equal but separate".

Facilities and services such as housing, healthcare, education, employment, and transportation have been systematically separated in the United States based on racial categorizations. Segregation was the legally or socially enforced separation of African Americans from whites, as well as the separation of other ethnic minorities from majority and mainstream communities. While mainly referring to the physical separation and provision of separate facilities, it can also refer to other manifestations such as prohibitions against interracial marriage, and the separation of roles within an institution. The U.S. Armed Forces were formally segregated until 1948, as black units were separated from white units but were still typically led by white officers.