Vipera berus sachalinensis (Sakhalin Island adder a.k.a. Sakhalin adder ) is a venomous viper subspecies endemic to Asia.
It is found in the Russian Far East (Amur), China (Jilin), North Korea, and on Sakhalin Island.
According to Schwarz (1936), the type locality is "Sachalin" (= Sakhalin Island, Russia).