Redoubt Volcano, or Mount Redoubt, is an active stratovolcano in the largely volcanic Aleutian Range of the U.S. state of Alaska. Located in the Chigmit Mountains subrange, the mountain is just west of Cook Inlet, in the Kenai Peninsula Borough about 180 km (110 mi) southwest of Anchorage. At 10,197 feet, in just over 5 miles (8 km) Mount Redoubt attains 9,150 feet (2,700 m) of prominence over its surrounding terrain. It is the highest summit in the Aleutian Range.

Active for millennia, Mount Redoubt has erupted five times since 1900: in 1902, 1922, 1966, 1989 and 2009. The eruption in 1989 spewed volcanic ash to a height of 45,000 ft (14,000 m) and caught KLM Flight 867, a Boeing 747 aircraft, in its plume; the flight landed safely at Anchorage. The ash blanketed an area of about 7,700 sq mi (20,000 km2). The 1989 eruption is also notable for being the first ever volcanic eruption to be successfully predicted by the method of long-period seismic events developed by Swiss/American volcanologist Bernard Chouet. The Alaska Volcano Observatory currently rates Redoubt as Aviation Alert Level Green and Volcano Alert Level Advisory.

The volcano is about 3.7 miles (6.0 km) in diameter at its base with a rough volume of 7.2–8.4 cu mi (30–35 km3). The sides of the upper cone are relatively steep (in comparison to volcanoes in general). Made up of pyroclastic flow deposits and lava flows, and resting on Mesozoic era rocks of the Aleutian Mountain Range batholith, the mountain has been somewhat weathered by movement of several glaciers that reside on it. The current main vent is on the north side of the crater by the head of the Drift glacier. Also present on the mountain are Holocene lahar deposits that extend as far as the Cook Inlet. This mountain has produced andesite, basalt and dacite, with relatively silicic andesite dominant in recent eruptions.