Mount Tendürek (Turkish: Tendürek Dağı; Armenian: Թոնդրակ, romanized: T’ondrak) is a shield volcano on the border of Ağrı and Van provinces in eastern Turkey, near the border with Iran. The volcano, which is mostly known for being near the supposed wreck site of Noah's Ark, is very large; its lava flows cover roughly 650 km² (251 mi²) across a swath of flat land. The mountain's two main features are the main summit crater Greater Tendürek, and a smaller crater known as Lesser Tendürek which lies to the east of the main crater. The slopes are very gentle and resemble a shield, after which the type is named. Mount Tendürek is known to have erupted viscous lava like that of volcanoes on the island of Hawaii.

The volcano is part of a volcanic group surrounding Lake Van that includes Nemrut Caldera and Mount Ararat. This group of volcanoes formed as a result of a continental collision that began roughly six million years ago and continued for the next few million years. Volcanicity in Tendürek started roughly 250,000 years ago and is still active. The most-recent eruption, a gas-and-ash eruption from the summit crater, occurred in 1855; this is also the most-recent eruption in Turkey. Since then, the volcano has mostly been geothermally active, emitting some steam and gases from the summits. Since 1993, the volcano's magma chamber has been subsiding, meaning the volcano is entering a dormancy phase.

Mount Tendürek is a shield volcano in far-eastern Turkey, approximately 950 km (590 mi) from the capital Ankara. The volcano is located northeast of Lake Van and roughly 25 km (16 mi) from Doğubeyazıt, which is the largest town in the vicinity. More than 170,000 people live within 30 km (19 mi) of the volcano, making it a potential threat to nearby settlements.

At the summit of Tendürek are two craters; the larger western peak has a height of 250 m (820 ft) and a diameter of 1 km (1 mi), and is the volcano's highest point, exceeding 3,500 m (11,483 ft). The eastern peak, which is called Lesser Tendürek (Küçük Tendürek in Turkish), is about 100 m (328 ft) high and has a diameter of 800 m (2,625 ft). The main crater's lava flows engulfed Lesser Tendürek, causing the elevation difference between the craters to decrease.

The western crater has a more prominent relief than the eastern crater; it is funnel-shaped and has a cylindrical trachytic spine in the east rim. The eastern crater is mostly flat and is filled with a warm lake.

Erupted volcanic material from these craters, mostly lava, covers roughly 650 km² (251 mi²). Following the main crater's formation, multiple eruptions along the flanks of the volcano with north–south-directed fissures occurred, forming trachyte domes and pāhoehoe lava flows, a viscous and very mobile lava type. These eruptions, until 2,500 years ago, expanded the area of lava-covered land.

Tendürek is in Turkey, which has some of the world's most-extensive seismic activity and deformation. The country is known for its extensive history of large and deadly earthquakes and is within the Mediterranean Earthquake Belt, a complex deformation zone caused by the collision between the African and the Eurasian tectonic plates.

The tectonics of Turkey are made up of three main elements: the Aegean-Cyprus Arc, a convergent plate boundary where the African Plate lithosphere subducts under the Anatolian Plate; the dextral strike-slip North Anatolian Fault, where the fault block moves horizontally rightwards against the block across the fault; and the sinistral strike-slip East Anatolian Fault, where the fault block moves horizontally leftwards against the block across the fault. The North and East Anatolian Faults are lengthy, strike-slip faults where the Anatolian Plate crust slides against the Arabian Plate and the Eurasian Plates to move westward from them. These two faults, in their eastern end, meet and form the Karlıova triple junction, a triple strike-slip collision zone.