Yemen Vilayet was a first-level administrative division (vilayet) of the Ottoman Empire. At the beginning of the 20th century it reportedly had an area of 200,000 square kilometres (77,200 sq mi). The population for the vilayet is given by the 1885 Ottoman census as 2,500,000.

A vilayet, also known by various other names, was a first-order administrative division of the later Ottoman Empire. It was introduced in the Vilayet Law of 21 January 1867, part of the Tanzimat reform movement initiated by the Ottoman Reform Edict of 1856. The Danube Vilayet had been specially formed in 1864 as an experiment under the leading reformer Midhat Pasha. The Vilayet Law expanded its use, but it was not until 1884 that it was applied to all of the empire's provinces. Writing for the Encyclopaedia Britannica in 1911, Vincent Henry Penalver Caillard claimed that the reform had intended to provide the provinces with greater amounts of local self-government but in fact had the effect of centralizing more power with the sultan and local Muslims at the expense of other communities.