Shimane Prefecture (島根県, Shimane-ken^?) is a prefecture of Japan located in the Chūgoku region on Honshū island. The capital is Matsue. It is the second least populous prefecture in Japan, after its eastern neighbor Tottori. The prefecture has an area elongated from east to west facing the Chūgoku Mountain Range on the south side and to the Sea of Japan on the north side. It is divided into the Izumo Region in the East, the Iwami Region in the West and the Oki Region, a small group of islands off the northern coast. Most of the cities are near the shoreline of the Sea of Japan. Izumo Taisha in Izumo City is one of the oldest Shinto shrines in Japan.

The Oki Islands in the Sea of Japan are also part of Shimane Prefecture, which also claims to have jurisdiction over the South Korea-controlled island of Liancourt Rocks (Takeshima).

The history of Shimane starts with the Japanese mythology. Shinto god Ōkuninushi was believed to be living in Izumo, an old province in Shimane. Izumo Shrine, which is in the city of Izumo, honors the god.　At that time, the current Shimane prefecture was divided in to three parts: Iwami, Izumo, and Oki. That lasted until the abolition of the han system took place in 1871. During the Nara period, Kakinomoto no Hitomaro read a poem on Shimane's nature when he was sent as the Royal governor.