Zaire (spelled Zaïre in French) was the name of the Second Republic of Democratic Republic of the Congo between 1971 and 1997. Although it came into use in 1971, the name Zaire is often still used for the portion of the Congo controlled by Mobutu since 1965. This article addresses this subsequent usage.

In 1960 the Belgian Congo gained its independence as the "Republic of the Congo" from Belgium. This was the same as a former French colony, Congo, with which it shares a border. In 1966 the Republic of the Congo added Democratic to become Democratic Republic of the Congo. However, the two countries are commonly distinguished by their capitals: Congo (Kinshasa) (then Congo (Léopoldville)) and Congo (Brazzaville). When General Joseph-Désiré Mobutu came to power in 1965, he embarked on an "authenticity" campaign. The country was thus renamed the Republic of Zaire. This decision was curious, given that the name Congo, which referred both to the river Congo and to the ancient Kongo Empire, was fundamentally "authentic" to pre-colonial African roots, while Zaire is in fact a Portugese corruption of another African word, Nzere ("river", by Nzadi o Nzere, "the river that swallow all the other rivers", another name of the Congo river). General Mobutu became Mobutu Sese Seko and forced all his citizens to adopt African names and many cities were also renamed. Some of the conversions are as follows:

• Léopoldville became Kinshasa
• Stanleyville became Kisangani
• Elisabethville became Lubumbashi
• Jadotville became Likasi
• Albertville became Kalemie

Additionally, the zaïre was introduced to replace the franc as the new national currency. 100 makuta (singular likuta) equaled one zaïre.

After Laurent-Desiré Kabila overthrew Mobutu in 1997, the country reverted to the name Democratic Republic of the Congo.

Zaire is also the name of a province of Angola; see Zaire Province. Zaire also referred to the Zaire River, another name for the Congo River, when the country was called Zaire.

Zaire, written in 1732, is also a tragedy by the French playwright/philosopher/poet Voltaire. It is ranked among the ten or twelve best plays of the entire French classical school.