The province of Tsushima (対馬国; Tsushima-No kuni ) was an old province of the Japan. It was also appelée' Taishū (対州).

The province of Tsushima was perhaps already recognized like province by the court of Yamato at the 5th century; it is however attested that under the system of the Ritsuryō it had this statute.

Districts

• Kamiagata (上県)

• Shimoagata (下県)

The capital of the province was the town of Izuhara.