Khadjibey (Turkish: Hacıbey; Ukrainian: Коцюбіїв) was a fortress and a haven by the Gulf of Odesa, in the location of the modern city of Odesa, Ukraine. The settlement was destroyed and abandoned in the 15th of 16th century and was revived under the Ottoman Empire in the 18th century.

Other known spellings include Khadzhibey, Khadjibei, Hajibey, Khacdjibei, Hacıbey, Hocabey, Gadzhibei, Chadžibėjus, Codjabey, Kachybey, Kotsiubey, Kotsiubiiv.

By one hypothesis, it was named after Hacı I Giray. Polish historian Marian Karol Dubiecki [pl] suggested the connection of the name of the fortress with the Polish roots linking it with the surname Kociuba, an opinion criticized by Vasili Nadler [ru].

Nadler suggested that a Tatar settlement existed on the site by the 14th century, but was ceded in the early 15th century to the Grand Duchy of Lithuania. An early mention of a "port Kaczubyeiow" dated 1415 is given by Jan Długosz in his Historiae Polonicae. However, it has been argued that Długosz erred and that the described events (the gift of grain by King Władysław II Jagiełło to a besieged Constantinople) are reliably documented to have happened in 1413.

In 1480, the fortress was captured by the Ottoman Empire. In 1764, the Ottomans reinforced their position by building the Yeni Dünya fortress nearby; the area was included in the province of Silistra Eyalet. The Russian army took the fortress and settlement in 1789 during the Russo-Turkish War, a battle was fought near Khadjibey in 1790, and, in 1792, the territory was annexed by the Russian Empire.

• Khadzhibey Estuary