The American Civil War has been known by a number of names since it began in 1861. These names reflect the historical, political, and cultural sensitivities of different groups and regions.

The most common name in modern American usage is simply the "Civil War". Although used rarely during the war, the term "War Between the States" became widespread afterward in the Southern United States. During and immediately after the war, Union forces often used the term "War of the Rebellion" or the "Great Rebellion", while the Confederate equivalent was "War for Southern Independence". The latter regained some currency in the late 20th century, but has again fallen out of use. Other terms often reflect a more partisan view of events, such as the "War of Northern Aggression", used by some Southerners, or the "Freedom War", used by their black counterparts to celebrate the effect the war had on ending slavery. In several European languages, the war is called "War of Secession".