Annaba (Arabic: عنابة, lit. 'place of the Jujubes'), formerly known as Bon, Bona and Bône, is a seaport city in the northeastern corner of Algeria, close to the border with Tunisia. Annaba is near the small Seybouse River and is in Annaba Province. With a population of about 263,650 (2019) and 1,000,000 for the metropolitan area, Annaba is the third-largest city and the leading industrial center in Algeria.

Annaba is a coastal city that underwent significant growth during the 20th century. Annaba has a metropolitan area with a higher population density than the other metropolitan areas of the Algerian coastline, such as Oran and Algiers. Much of eastern and southern Algeria uses the services, equipment and infrastructure of Annaba. Economically, it is the centre for various economic activities, such as industry, transportation, finance, and tourism.

Present-day Annaba grew up on the site of Aphrodisium, the seaport of the Roman city Hippo Regius. (The modern city has since expanded south over Hippo's ruins as well.) Its former names Bône and Bona derived from "Ubbo", a local form of the name Hippo. Its informal name "Land of the Jujubes" (بلد العناب, Balad al-‘Unnāb) derives from the abundance of that fruit in the region.

The area of Annaba has yielded evidence of very early human occupation at Ain el Hanech, near Saïda (circa 200,000 BC), including artifacts that show remarkable toolmaking craftsmanship. According to some sources, prehistoric Algeria was the site of the most advanced development of flake-tool techniques in the Middle Early Stone Age (Middle Paleolithic).

The town of Hippo Regius (modern Annaba) first entered historical records at the end of the 3rd century BCE as a possession of Massinissa's Numidian Kingdom. Augustine of Hippo was bishop here from 396 AD until his death in 430 AD. The city was destroyed in the 5th century by the Vandals. Vandals ruled the city for roughly a century until 534. Gelimer, the King of the Vandals and Alans from 530 to 534 AD, faced with the starvation of his followers and their children, and realizing he had no chance of regaining his kingdom of North Africa, surrendered to Flavius Belisarius, a general of the Byzantine Empire under Justinian I, at Bône. Byzantines then ruled Hippona (Hippo's new name after 395) before the Muslim conquest of the Maghreb in 699 AD. Later, Abbasids, Aghlabids, and Fatimids ruled Bona before the rise of the Zirids. It was relocated to its present place after flooding and Banu Hilal the ravages that occurred in 1033 during Hammadid rule. It was attacked by a Pisan fleet in 1034 and was conquered by Kingdom of Sicily in 1153. The Almohads took it in 1160.

Al-Bakri, in the 11th century, wrote about the city:

"Bona is an ancient city, it is the city of Augustine, the scholar of Christianity. It is located on the coast of the sea, on a high and fortified piece of land overlooking the city of Seboussa. Today, it is called the city of Zawa, and it is about three miles away from the modern city. It has mosques, markets, and a public bath. The land is fertile, with fruits and crops. The modern city of Bona was surrounded by walls after the year 450 [Hijri year]. In the modern city of Bona, there is a well by the sea, carved in solid rock, called the well of Nithra, from which most of the inhabitants drink."

During the 11th century, the Banu Hilal, an Arab tribe living between the Nile and the Red Sea, settled in Tunisia, Tripolitania (western Libya) and Constantinois (eastern Algeria) which was the portion known as Annaba.