Poronaysk (; , Shisuka; Ainu: Sistukari or Sisi Tukari) is a town and the administrative center of Poronaysky District of Sakhalin Oblast, Russia, located on the Poronay River  north of Yuzhno-Sakhalinsk. Population:

It was founded in 1869 as a Russian outpost Tikhmenevsky near the Nivkh and Ainu settlements in the area. The Treaty of Portsmouth transferred it to Japanese control along with the rest of the southern half of the island of Sakhalin. It was renamed , remaining under Japanese control until the Soviet Army retook the whole of the island in 1945.