Numidia (202 BC – 46 BC) was an ancient Berber kingdom in modern-day Algeria and a smaller part of western Tunisia in North Africa. Numidia was originally divided between Massyliis in Eastern Numidia with Massinissa and Masaesylis in Western Numidia diriged by Syphax. It is Massinissa who historically won over Syphax and unified Numidia into one kingdom. The kingdom began as a sovereign state and later alternated between being a Roman province and being a Roman client state. The kingdom is no longer in existence today. It was located in modern Algeria, bordered by the kingdoms of Mauretania (modern-day Morocco) to the west, the Roman province of Africa (modern-day Tunisia) to the east, the Mediterranean Sea to the north, and the Sahara Desert to the south. Its people were the Numidian Berbers. It is considered to be the first major state in the history of Algeria and the Berber world.

The name Numidia was first applied by Polybius and other historians during the third century BC to indicate the territory west of Carthage, including the entire north of Algeria as far as the river Mulucha (Muluya), about 100 miles west of Oran. The Numidians were conceived of as two great tribal groups: the Massylii in eastern Numidia, and the Masaesyli in the west.