Strait of Tartary (Gulf of Tartary, Gulf of Tatary, Tatar Strait, Tartar Strait, Strait of Tartar, also Mamiya Strait and Strait of Nevelskoi) strait in the Pacific Ocean dividing the Russian island of Sakhalin from mainland Asia (South-East Russia), connecting the Sea of Okhotsk on the north with the Sea of Japan on the south. It is 900 km long, 4-20 m deep, and 7.3 km wide at the narrowest point.

The name Tartar, or Tatars comes from an out-of-date name for Asia.

In Japan, the strait is named after Mamiya Rinzo, who sailed the strait in 1808, while Russian authors prefer to name it after Admiral Nevelskoi, who explored the area in 1848.

Strait of Tartary is also a poem by Walter de la Mare, in which he speaks about Tartary as a land in Asia north of China.