Klyuchevskaya Sopka (Russian: Ключевская сопка; also known as Klyuchevskoi, Russian: Ключевской) is a stratovolcano, the highest mountain on the Kamchatka Peninsula of Russia and the highest active volcano of Eurasia. Its steep, symmetrical cone towers about 100 kilometres (60 mi) from the Bering Sea. The volcano is part of the natural Volcanoes of Kamchatka UNESCO World Heritage Site.

Klyuchevskaya's first recorded eruption occurred in 1697, and it has been almost continuously active ever since, as have many of its neighboring volcanoes. It was first climbed in 1788 by Daniel Gauss and two other members of the Billings Expedition. No other ascents were recorded until 1931, when several climbers were killed by flying lava on the descent. As similar dangers still exist today, few ascents are made.

Klyuchevskaya Sopka is considered sacred by some indigenous peoples, being viewed by them as the location at which the world was created. Other volcanoes in the region are seen with similar spiritual significance, but Klyuchevskaya Sopka is the most sacred of these.