Tosu (鳥栖市, Tosu-shi) is a city located in the eastern part of Saga Prefecture on the island of Kyushu, Japan.

[3] The area of Tosu was part of ancient Hizen Province, and during the Edo period was an exclave of Tsushima-Fuchū Domain under the Tokugawa shogunate.

The Sō clan prospered from its knowledge of Chinese traditional medicine and access to supplies imported from Korea, and the region was considered one of the four major pharmaceutical centers in pre-modern Japan.

Following the Meiji restoration, the area was the center of the 1874 Saga Rebellion, and a battle between the government troops and the rebel army occurred on Mount Asahi.

The villages Asahi, Fumoto, Kizato, Tashiro and Todoroki were created on April 1, 1889 with the establishment of the modern municipalities system.

Tosu is a regional commercial center and logistics and distribution hub, due to its location at the intersection of several major highways and rail line.