Sibiryakov Island or Sibiryakow Island (Russian: Остров Сибирякова, Ostrov Sibiryakova), also known as Kuz'kin Island (Кузькин остров), is an island of 800 square kilometres (310 square miles). Its length is 38 kilometres (24 miles) and its maximum width 27 kilometres (17 miles). It is covered with tundra vegetation.
The sea surrounding Sibiryakov Island is covered with pack ice in the winter and there are numerous ice floes even in the summer. The strait between Sibiryakov Island and the mainland is known as Vostochnyy Proliv.
This island is named after Aleksandr Mikhaylovich Sibiryakov, an Imperial Russian gold-mine proprietor. Sibiryakov financed explorations to Siberia, such as Nordenskiöld's, and also took part in some expeditions of his own.
12 km off Sibiryakov Island's northern cape lies a narrow and curved group of three islands known as Nosok Island (Остров Носок; Ostrov Nosok).