Bessarabia is a former region of Eastern Europe comprising most of current-day Moldova and districts of Ukraine. It is bounded by the Dniestr river to the north and east, the Prut to the west and the lower Danube river and the Black Sea to the south.

The region's main cities are Chişinău, the capital of Moldova, Tiraspol, Izmayil and Bilhorod-Dnistrovs'ki. The name Bessarabia (in Romanian, Basarabia) is probably derived from the Wallachian family of Basarab, once rulers over part of the area.

Greek settlers established colonies in the region in the 7th century BCE. Bessarabia was part of the Dacian kingdoms ruled by Burebista in 1st century BC and by Decebalus in the 1st century AD. After the Roman Empire conquered a part of Dacia, some Dacians (the free Dacians) resisted the Roman conquerors in Bessarabia.

The region was later frequently invaded: by Goths, Huns, Avars, Magyars, Cumans and Mongols. Through the Middle Ages, Bessarabia was a part of the principality of Moldavia, falling thereafter under the rule of the Ottoman Empire.

In 1812, the Treaty of Bucharest gave the region to Russia. After the Crimean War, the southern part was handed over to Moldavia, but this reverted to Russian rule in 1878. After the Russian Revolution, the area declared itself an independent republic, but the local National Council decided upon union with Romania. The union was confirmed by Romania's western allies in the Treaty of Paris (1920), but not recognised by the Soviet Union.

In June 1940, Romania had to cede the region to the Soviet Union, which divided it between the Moldavian Soviet Socialist Republic and the Ukrainian SSR. Bessarabia's northern and southern districts (largely inhabited by Ukrainians and Romanians) were exchanged with Transnistria (the districts on the left or eastern bank of the Dniestr, largely inhabited by Russians). Following the Soviet takeover, many Moldavians of Romanian origin were deported to Siberia and Kazakhstan.

When the Moldavian SSR became the independent Republic of Moldova in August 1991, its boundaries remained unchanged.