The Akhtuba (Russian: А́хтуба); also transliterated Achtuba on some maps) is a left distributary of the Volga in southern Russia.^[1]

The Akhtuba splits off the Volga shortly before the city of Volgograd (at 48°49′00″N 44°41′17″E / 48.8167°N 44.6880°E / 48.8167; 44.6880), and flows toward the Volga Delta and Caspian Sea. The old beginning of Akhtuba was blocked by the dam of the Volga Hydroelectric Station; now it flows from the Volga via an artificial outtake canal 6.5 kilometres (4.0 mi) long that starts below the dam. The river is 537 kilometres (334 mi) long; the average water flow is 153 cubic metres per second (5,400 cu ft/s).

The following cities lie on or near the Akhtuba: Volzhsky (at the beginning of the river), Leninsk, Znamensk, Akhtubinsk, Kharabali (within 5 kilometres of the river). The capital of the Golden Horde, Sarai Batu, was most likely located along the Akhtuba as well, not far from Kharabali.^{[citation needed]}

The area between the Volga and the Akhtuba is known as the Volga-Akhtuba plain, which is one of Russia's primary vegetable-growing regions. It is particularly well known as a major source of watermelons consumed in Russia.