The Vilayet of the Danube or Danubian Vilayet (Ottoman Turkish: ولايت طونه, Vilâyet-i Tuna) was a first-level administrative division (vilayet) of the Ottoman Empire from 1864 to 1878. In the late 19th century it reportedly had an area of 34,120 square miles (88,400 km2).
The vilayet was created from the northern parts of Silistra Province along the Danube River and eyalets of Niš, Vidin and Silistra. This vilayet was meant to become a model province, showcasing all the progress achieved by the Porte through the modernising Tanzimat reforms. Other vilayets modelled on the vilayet of the Danube were ultimately established throughout the empire by 1876, with the exception of the Arabian peninsula and the by then semi-independent Egypt. Rusçuk, today Ruse in Bulgaria, was chosen as the capital of the vilayet due to its position as a key Ottoman port on the Danube.
The province disappeared after the Russo-Turkish War of 1877–78, when its north-eastern part (Northern Dobruja) was incorporated into Romania, some of its western territories into Serbia, while the central and southern regions made up most of the autonomous principality of Bulgaria and a part of Eastern Rumelia.