Avachinsky (also known as Avacha or Avacha Volcano or Avachinskaya Sopka) (Russian: Авачинская сопка, Авача) is an active stratovolcano in Russia. It is situated on the Kamchatka Peninsula in the Russian Far East. Avachinsky lies within sight of Petropavlovsk-Kamchatsky, the capital of Kamchatka Krai. Together with neighbouring Koryaksky volcano, it is considered a Decade Volcano, worthy of particular study in light of its history of explosive eruptions and proximity to populated areas.

Avachinsky's last eruption occurred in 2008. This eruption was tiny compared to the volcano's major Volcanic Explosivity Index 4 eruption in 1945.